v3.5.4

This fixes compilation issue with C++23 mode against libstdc++.

Closes #2852

.clang-tidy

@@ -0,0 +1,81 @@
+---
+# Note: Alas, `Checks` is a string, not an array.
+#       Comments in the block string are not parsed and are passed in the value.
+#       They must thus be delimited by ',' from either side - then they are
+#       harmless. It's terrible, but it works.
+Checks: >-
+  clang-diagnostic-*,
+  clang-analyzer-*,
+  -clang-analyzer-optin.core.EnumCastOutOfRange,
+
+  bugprone-*,
+  -bugprone-unchecked-optional-access,
+  ,# This is ridiculous, as it triggers on constants,
+  -bugprone-implicit-widening-of-multiplication-result,
+  -bugprone-easily-swappable-parameters,
+  ,# Is not really useful, has false positives, triggers for no-noexcept move constructors ...,
+  -bugprone-exception-escape,
+  -bugprone-narrowing-conversions,
+  -bugprone-chained-comparison,# RIP decomposers,
+
+  modernize-*,
+  -modernize-avoid-c-arrays,
+  -modernize-use-auto,
+  -modernize-use-emplace,
+  -modernize-use-nullptr,# it went crazy with three-way comparison operators,
+  -modernize-use-trailing-return-type,
+  -modernize-return-braced-init-list,
+  -modernize-concat-nested-namespaces,
+  -modernize-use-nodiscard,
+  -modernize-use-default-member-init,
+  -modernize-type-traits,# we need to support C++14,
+  -modernize-deprecated-headers,
+  ,# There's a lot of these and most of them are probably not useful,
+  -modernize-pass-by-value,
+
+  performance-*,
+  -performance-enum-size,
+
+  portability-*,
+
+  readability-*,
+  -readability-braces-around-statements,
+  -readability-container-size-empty,
+  -readability-convert-member-functions-to-static,
+  -readability-else-after-return,
+  -readability-function-cognitive-complexity,
+  -readability-function-size,
+  -readability-identifier-length,
+  -readability-implicit-bool-conversion,
+  -readability-isolate-declaration,
+  -readability-magic-numbers,
+  -readability-named-parameter,
+  -readability-qualified-auto,
+  -readability-redundant-access-specifiers,
+  -readability-simplify-boolean-expr,
+  -readability-static-definition-in-anonymous-namespace,
+  -readability-uppercase-literal-suffix,
+  -readability-use-anyofallof,
+  -readability-avoid-return-with-void-value,
+
+  ,# time hogs,
+  -bugprone-throw-keyword-missing,
+  -modernize-replace-auto-ptr,
+  -readability-identifier-naming,
+
+  ,# We cannot use this until clang-tidy supports custom unique_ptr,
+  -bugprone-use-after-move,
+  ,# Doesn't recognize unevaluated context in CATCH_MOVE and CATCH_FORWARD,
+  -bugprone-macro-repeated-side-effects,
+WarningsAsErrors: >-
+  clang-analyzer-core.*,
+  clang-analyzer-cplusplus.*,
+  clang-analyzer-security.*,
+  clang-analyzer-unix.*,
+  performance-move-const-arg,
+  performance-unnecessary-value-param,
+  readability-duplicate-include,
+HeaderFilterRegex: '.*\.(c|cxx|cpp)$'
+FormatStyle:     none
+CheckOptions: {}
+...

.conan/test_package/CMakeLists.txt

@@ -1,12 +1,8 @@
-cmake_minimum_required(VERSION 3.2.0)
-project(test_package CXX)
+cmake_minimum_required(VERSION 3.15)
+project(PackageTest CXX)
 
-include("${CMAKE_BINARY_DIR}/conanbuildinfo.cmake")
-conan_basic_setup()
+find_package(Catch2 CONFIG REQUIRED)
 
-find_package(Catch2 REQUIRED CONFIG)
-
-add_executable(${PROJECT_NAME} test_package.cpp)
-
-target_link_libraries(${PROJECT_NAME} Catch2::Catch2WithMain)
-set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 14)
+add_executable(test_package test_package.cpp)
+target_link_libraries(test_package Catch2::Catch2WithMain)
+target_compile_features(test_package PRIVATE cxx_std_14)

.conan/test_package/conanfile.py

@@ -1,12 +1,28 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-from conans import ConanFile, CMake
+from conan import ConanFile
+from conan.tools.cmake import CMake, cmake_layout
+from conan.tools.build import can_run
+from conan.tools.files import save, load
 import os
 
 
 class TestPackageConan(ConanFile):
     settings = "os", "compiler", "build_type", "arch"
-    generators = "cmake_find_package_multi", "cmake"
+    generators = "CMakeToolchain", "CMakeDeps", "VirtualRunEnv"
+    test_type = "explicit"
+
+    def requirements(self):
+        self.requires(self.tested_reference_str)
+
+    def layout(self):
+        cmake_layout(self)
+
+    def generate(self):
+        save(self, os.path.join(self.build_folder, "package_folder"),
+             self.dependencies[self.tested_reference_str].package_folder)
+        save(self, os.path.join(self.build_folder, "license"),
+             self.dependencies[self.tested_reference_str].license)
 
     def build(self):
         cmake = CMake(self)
@@ -14,7 +30,11 @@ class TestPackageConan(ConanFile):
         cmake.build()
 
     def test(self):
-        assert os.path.isfile(os.path.join(
-            self.deps_cpp_info["catch2"].rootpath, "licenses", "LICENSE.txt"))
-        bin_path = os.path.join("bin", "test_package")
-        self.run("%s -s" % bin_path, run_environment=True)
+        if can_run(self):
+            cmd = os.path.join(self.cpp.build.bindir, "test_package")
+            self.run(cmd, env="conanrun")
+
+            package_folder = load(self, os.path.join(self.build_folder, "package_folder"))
+            license = load(self, os.path.join(self.build_folder, "license"))
+            assert os.path.isfile(os.path.join(package_folder, "licenses", "LICENSE.txt"))
+            assert license == 'BSL-1.0'

.github/workflows/linux-meson-builds.yml

@@ -40,6 +40,5 @@ jobs:
 
     - name: Run tests
       working-directory: ${{runner.workspace}}/meson-build
-      # Hardcode 2 cores we know are there
       run: |
         meson test --verbose

.github/workflows/linux-other-builds.yml

@@ -102,5 +102,53 @@ jobs:
       env:
           CTEST_OUTPUT_ON_FAILURE: 1
       working-directory: ${{runner.workspace}}/build
-      # Hardcode 2 cores we know are there
-      run: ctest -C ${{matrix.build_type}} -j 2 ${{matrix.other_ctest_args}}
+      run: ctest -C ${{matrix.build_type}} -j `nproc` ${{matrix.other_ctest_args}}
+  clang-tidy:
+    name: clang-tidy ${{matrix.version}}, ${{matrix.build_description}}, C++${{matrix.std}} ${{matrix.build_type}}
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        include:
+          - version: "15"
+            build_description: all
+            build_type: Debug
+            std: 17
+            other_pkgs: ''
+            cmake_configurations: -DCATCH_BUILD_EXAMPLES=ON -DCATCH_ENABLE_CMAKE_HELPER_TESTS=ON
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Prepare environment
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y ninja-build clang-${{matrix.version}} clang-tidy-${{matrix.version}} ${{matrix.other_pkgs}}
+
+    - name: Configure build
+      working-directory: ${{runner.workspace}}
+      env:
+        CXX: clang++-${{matrix.version}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      # Note: $GITHUB_WORKSPACE is distinct from ${{runner.workspace}}.
+      #       This is important
+      run: |
+        clangtidy="clang-tidy-${{matrix.version}};-use-color"
+        # Use a dummy compiler/linker/ar/ranlib to effectively disable the
+        # compilation and only run clang-tidy.
+        cmake -Bbuild -H$GITHUB_WORKSPACE \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_STANDARD_REQUIRED=ON \
+              -DCMAKE_CXX_EXTENSIONS=OFF \
+              -DCATCH_DEVELOPMENT_BUILD=ON \
+              -DCMAKE_CXX_CLANG_TIDY="$clangtidy" \
+              -DCMAKE_CXX_COMPILER_LAUNCHER=/usr/bin/true \
+              -DCMAKE_AR=/usr/bin/true \
+              -DCMAKE_CXX_COMPILER_AR=/usr/bin/true \
+              -DCMAKE_RANLIB=/usr/bin/true \
+              -DCMAKE_CXX_LINK_EXECUTABLE=/usr/bin/true \
+              ${{matrix.cmake_configurations}} \
+              -G Ninja
+
+    - name: Run clang-tidy
+      working-directory: ${{runner.workspace}}/build
+      run: ninja

.github/workflows/linux-simple-builds.yml

@@ -120,5 +120,4 @@ jobs:
       env:
           CTEST_OUTPUT_ON_FAILURE: 1
       working-directory: ${{runner.workspace}}/build
-      # Hardcode 2 cores we know are there
-      run: ctest -C ${{matrix.build_type}} -j 2
+      run: ctest -C ${{matrix.build_type}} -j `nproc`

.github/workflows/mac-builds-m1.yml

@@ -0,0 +1,44 @@
+name: M1 Mac builds
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: macos-14
+    strategy:
+      matrix:
+        cxx:
+          - clang++
+        build_type: [Debug, Release]
+        std: [14, 17]
+        include:
+          - build_type: Debug
+            examples: ON
+            extra_tests: ON
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Configure build
+      working-directory: ${{runner.workspace}}
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      run: |
+        cmake -Bbuild -H$GITHUB_WORKSPACE \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_STANDARD_REQUIRED=ON \
+              -DCATCH_DEVELOPMENT_BUILD=ON \
+              -DCATCH_BUILD_EXAMPLES=${{matrix.examples}} \
+              -DCATCH_BUILD_EXTRA_TESTS=${{matrix.examples}}
+
+    - name: Build tests + lib
+      working-directory: ${{runner.workspace}}/build
+      run: make -j `sysctl -n hw.ncpu`
+
+    - name: Run tests
+      env:
+          CTEST_OUTPUT_ON_FAILURE: 1
+      working-directory: ${{runner.workspace}}/build
+      run: ctest -C ${{matrix.build_type}} -j `sysctl -n hw.ncpu`

.github/workflows/package-manager-builds.yaml

@@ -0,0 +1,31 @@
+name: Package Manager Builds
+
+on: [push, pull_request]
+
+jobs:
+  conan_builds:
+    name: Conan ${{matrix.conan_version}}
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        conan_version:
+          - '1.63'
+          - '2.1'
+
+        include:
+          # Conan 1 has default profiles installed
+          - conan_version: '1.63'
+            profile_generate: 'false'
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install conan
+      run: pip install conan==${{matrix.conan_version}}
+
+    - name: Setup conan profiles
+      if: matrix.profile_generate != 'false'
+      run: conan profile detect
+
+    - name: Run conan package create
+      run: conan create . -tf .conan/test_package

.gitignore

@@ -25,6 +25,7 @@ Build
 cmake-build-*
 benchmark-dir
 .conan/test_package/build
+.conan/test_package/CMakeUserPresets.json
 bazel-*
 build-fuzzers
 debug-build

CMakeLists.txt

@@ -33,7 +33,7 @@ if (CMAKE_BINARY_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
 endif()
 
 project(Catch2
-  VERSION 3.5.2 # CML version placeholder, don't delete
+  VERSION 3.5.4 # CML version placeholder, don't delete
   LANGUAGES CXX
   # HOMEPAGE_URL is not supported until CMake version 3.12, which
   # we do not target yet.
@@ -200,4 +200,4 @@ if (NOT_SUBPROJECT)
 
     include( CPack )
 
-endif(NOT_SUBPROJECT)
+endif()

appveyor.yml

@@ -5,10 +5,10 @@ version: "{build}-{branch}"
 clone_depth: 20
 
 # We want to build everything, except for branches that are explicitly
-# for messing around with travis.
+# for messing around with Github Actions.
 branches:
   except:
-    - /dev-travis.+/
+    - /devel-gha.+/
 
 
 # We need a more up to date pip because Python 2.7 is EOL soon
@@ -70,3 +70,14 @@ environment:
       additional_flags: "/permissive- /std:c++latest"
       platform: x64
       configuration: Debug
+
+    - FLAVOR: VS 2017 x64 Debug
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x64
+      configuration: Debug
+
+    - FLAVOR: VS 2017 x64 Release Coverage
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      coverage: 1
+      platform: x64
+      configuration: Debug

conanfile.py

@@ -1,5 +1,14 @@
 #!/usr/bin/env python
-from conans import ConanFile, CMake, tools
+from conan import ConanFile
+from conan.tools.cmake import CMake, CMakeToolchain, CMakeDeps, cmake_layout
+from conan.tools.files import copy, rmdir
+from conan.tools.build import check_min_cppstd
+from conan.tools.scm import Version
+from conan.errors import ConanInvalidConfiguration
+import os
+import re
+
+required_conan_version = ">=1.53.0"
 
 class CatchConan(ConanFile):
     name = "catch2"
@@ -8,53 +17,111 @@ class CatchConan(ConanFile):
     url = "https://github.com/catchorg/Catch2"
     homepage = url
     license = "BSL-1.0"
-
-    exports = "LICENSE.txt"
-    exports_sources = ("src/*", "CMakeLists.txt", "CMake/*", "extras/*")
-
+    version = "latest"
     settings = "os", "compiler", "build_type", "arch"
 
-    generators = "cmake"
+    options = {
+        "shared": [True, False],
+        "fPIC": [True, False],
+    }
+    default_options = {
+        "shared": False,
+        "fPIC": True,
+    }
 
-    def _configure_cmake(self):
-        cmake = CMake(self)
-        cmake.definitions["BUILD_TESTING"] = "OFF"
-        cmake.definitions["CATCH_INSTALL_DOCS"] = "OFF"
-        cmake.definitions["CATCH_INSTALL_EXTRAS"] = "ON"
-        cmake.configure(build_folder="build")
-        return cmake
+    @property
+    def _min_cppstd(self):
+        return "14"
+
+    @property
+    def _compilers_minimum_version(self):
+        return {
+            "gcc": "7",
+            "Visual Studio": "15",
+            "msvc": "191",
+            "clang": "5",
+            "apple-clang": "10",
+        }
+
+
+    def set_version(self):
+        pattern = re.compile(r"\w*VERSION (\d+\.\d+\.\d+) # CML version placeholder, don't delete")
+        with open("CMakeLists.txt") as file:
+            for line in file:
+                result = pattern.search(line)
+                if result:
+                    self.version = result.group(1)
+
+        self.output.info(f'Using version: {self.version}')
+
+    def export(self):
+        copy(self, "LICENSE.txt", src=self.recipe_folder, dst=self.export_folder)
+
+    def export_sources(self):
+        copy(self, "CMakeLists.txt", src=self.recipe_folder, dst=self.export_sources_folder)
+        copy(self, "src/*", src=self.recipe_folder, dst=self.export_sources_folder)
+        copy(self, "extras/*", src=self.recipe_folder, dst=self.export_sources_folder)
+        copy(self, "CMake/*", src=self.recipe_folder, dst=self.export_sources_folder)
+
+    def config_options(self):
+        if self.settings.os == "Windows":
+            del self.options.fPIC
+
+    def configure(self):
+        if self.options.shared:
+            self.options.rm_safe("fPIC")
+
+    def layout(self):
+        cmake_layout(self)
+
+    def validate(self):
+        if self.settings.compiler.get_safe("cppstd"):
+            check_min_cppstd(self, self._min_cppstd)
+        # INFO: Conan 1.x does not specify cppstd by default, so we need to check the compiler version instead.
+        minimum_version = self._compilers_minimum_version.get(str(self.settings.compiler), False)
+        if minimum_version and Version(self.settings.compiler.version) < minimum_version:
+            raise ConanInvalidConfiguration(f"{self.ref} requires C++{self._min_cppstd}, which your compiler doesn't support")
+
+    def generate(self):
+        tc = CMakeToolchain(self)
+        tc.cache_variables["BUILD_TESTING"] = False
+        tc.cache_variables["CATCH_INSTALL_DOCS"] = False
+        tc.cache_variables["CATCH_INSTALL_EXTRAS"] = True
+        tc.generate()
+
+        deps = CMakeDeps(self)
+        deps.generate()
 
     def build(self):
-        # We need this workaround until the toolchains feature
-        # to inject stuff like MD/MT
-        line_to_replace = 'list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/CMake")'
-        tools.replace_in_file("CMakeLists.txt", line_to_replace,
-                              '''{}
-include("{}/conanbuildinfo.cmake")
-conan_basic_setup()'''.format(line_to_replace, self.install_folder.replace("\\", "/")))
-
-        cmake = self._configure_cmake()
+        cmake = CMake(self)
+        cmake.configure()
         cmake.build()
 
     def package(self):
-        self.copy(pattern="LICENSE.txt", dst="licenses")
-        cmake = self._configure_cmake()
+        copy(self, "LICENSE.txt", src=str(self.recipe_folder), dst=os.path.join(self.package_folder, "licenses"))
+        cmake = CMake(self)
         cmake.install()
+        rmdir(self, os.path.join(self.package_folder, "share"))
+        rmdir(self, os.path.join(self.package_folder, "lib", "cmake"))
+        copy(self, "*.cmake", src=os.path.join(self.export_sources_folder, "extras"),
+                              dst=os.path.join(self.package_folder, "lib", "cmake", "Catch2"))
 
     def package_info(self):
         lib_suffix = "d" if self.settings.build_type == "Debug" else ""
 
-        self.cpp_info.names["cmake_find_package"] = "Catch2"
-        self.cpp_info.names["cmake_find_package_multi"] = "Catch2"
+        self.cpp_info.set_property("cmake_file_name", "Catch2")
+        self.cpp_info.set_property("cmake_target_name", "Catch2::Catch2WithMain")
+        self.cpp_info.set_property("pkg_config_name", "catch2-with-main")
+
         # Catch2
-        self.cpp_info.components["catch2base"].names["cmake_find_package"] = "Catch2"
-        self.cpp_info.components["catch2base"].names["cmake_find_package_multi"] = "Catch2"
-        self.cpp_info.components["catch2base"].names["pkg_config"] = "Catch2"
+        self.cpp_info.components["catch2base"].set_property("cmake_file_name", "Catch2::Catch2")
+        self.cpp_info.components["catch2base"].set_property("pkg_config_name", "catch2")
         self.cpp_info.components["catch2base"].libs = ["Catch2" + lib_suffix]
         self.cpp_info.components["catch2base"].builddirs.append("lib/cmake/Catch2")
+
         # Catch2WithMain
-        self.cpp_info.components["catch2main"].names["cmake_find_package"] = "Catch2WithMain"
-        self.cpp_info.components["catch2main"].names["cmake_find_package_multi"] = "Catch2WithMain"
-        self.cpp_info.components["catch2main"].names["pkg_config"] = "Catch2WithMain"
+        self.cpp_info.components["catch2main"].set_property("cmake_file_name", "Catch2::Catch2WithMain")
+        self.cpp_info.components["catch2main"].set_property("cmake_target_name", "Catch2::Catch2WithMain")
+        self.cpp_info.components["catch2main"].set_property("pkg_config_name", "catch2-with-main")
         self.cpp_info.components["catch2main"].libs = ["Catch2Main" + lib_suffix]
         self.cpp_info.components["catch2main"].requires = ["catch2base"]

docs/cmake-integration.md

@@ -384,7 +384,7 @@ install it to the default location, like so:
 ```
 $ git clone https://github.com/catchorg/Catch2.git
 $ cd Catch2
-$ cmake -Bbuild -H. -DBUILD_TESTING=OFF
+$ cmake -B build -S . -DBUILD_TESTING=OFF
 $ sudo cmake --build build/ --target install
 ```
 
@@ -408,6 +408,24 @@ cd vcpkg
 The catch2 port in vcpkg is kept up to date by microsoft team members and community contributors.
 If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
 
+## Installing Catch2 from Bazel
+
+Catch2 is now a supported module in the Bazel Central Registry. You only need to add one line to your MODULE.bazel file;
+please see https://registry.bazel.build/modules/catch2 for the latest supported version.
+
+You can then add `catch2_main` to each of your C++ test build rules as follows:
+
+```
+cc_test(
+    name = "example_test",
+    srcs = ["example_test.cpp"],
+    deps = [
+        ":example",
+        "@catch2//:catch2_main",
+    ],
+)
+```
+
 ---
 
 [Home](Readme.md#top)

docs/command-line.md

@@ -145,7 +145,7 @@ only tests that match the positive filters are included.
 
 You can also match test names with special characters by escaping them
 with a backslash (`"\"`), e.g. a test named `"Do A, then B"` is matched
-by "Do A\, then B" test spec. Backslash also escapes itself.
+by `"Do A\, then B"` test spec. Backslash also escapes itself.
 
 
 ### Examples
@@ -194,7 +194,8 @@ verbose and human-friendly output.
 
 Reporters are also individually configurable. To pass configuration options
 to the reporter, you append `::key=value` to the reporter specification
-as many times as you want, e.g. `--reporter xml::out=someFile.xml`.
+as many times as you want, e.g. `--reporter xml::out=someFile.xml` or
+`--reporter custom::colour-mode=ansi::Xoption=2`.
 
 The keys must either be prefixed by "X", in which case they are not parsed
 by Catch2 and are only passed down to the reporter, or one of options
@@ -365,14 +366,14 @@ There are currently two warnings implemented:
 ## Reporting timings
 <pre>-d, --durations &lt;yes/no></pre>
 
-When set to ```yes``` Catch will report the duration of each test case, in milliseconds. Note that it does this regardless of whether a test case passes or fails. Note, also, the certain reporters (e.g. Junit) always report test case durations regardless of this option being set or not.
+When set to ```yes``` Catch will report the duration of each test case, in seconds with millisecond precision. Note that it does this regardless of whether a test case passes or fails. Note, also, the certain reporters (e.g. Junit) always report test case durations regardless of this option being set or not.
 
 <pre>-D, --min-duration &lt;value></pre>
 
 > `--min-duration` was [introduced](https://github.com/catchorg/Catch2/pull/1910) in Catch2 2.13.0
 
 When set, Catch will report the duration of each test case that took more
-than &lt;value> seconds, in milliseconds. This option is overridden by both
+than &lt;value> seconds, in seconds with millisecond precision. This option is overridden by both
 `-d yes` and `-d no`, so that either all durations are reported, or none
 are.
 

docs/generators.md

@@ -206,12 +206,26 @@ or OO ranges.
 Unlike `std::uniform_int_distribution`, Catch2's generators also support
 various single-byte integral types, such as `char` or `bool`.
 
-Given the same seed, the output from the integral generators is
-reproducible across different platforms. For floating point generators,
-we only promise reproducibility on platforms that obey the IEEE 754
-standard, and where `float` is 4 bytes and `double` is 8 bytes. We provide
-no guarantees for `long double`, as the internals of `long double` can
-vary wildly across different platforms.
+
+#### Reproducibility
+
+Given the same seed, the output from the integral generators is fully
+reproducible across different platforms.
+
+For floating point generators, the situation is much more complex.
+Generally Catch2 only promises reproducibility (or even just correctness!)
+on platforms that obey the IEEE-754 standard. Furthermore, reproducibility
+only applies between binaries that perform floating point math in the
+same way, e.g. if you compile a binary targetting the x87 FPU and another
+one targetting SSE2 for floating point math, their results will vary.
+Similarly, binaries compiled with compiler flags that relax the IEEE-754
+adherence, e.g. `-ffast-math`, might provide different results than those
+compiled for strict IEEE-754 adherence.
+
+Finally, we provide zero guarantees on the reproducibility of generating
+`long double`s, as the internals of `long double` varies across different
+platforms.
+
 
 
 ## Generator interface

docs/limitations.md

@@ -173,3 +173,19 @@ TEST_CASE("b") {
 
 If you are seeing a problem like this, i.e. weird test paths that trigger only under Clang with `libc++`, or only under very specific version of `libstdc++`, it is very likely you are seeing this. The only known workaround is to use a fixed version of your standard library.
 
+
+### Visual Studio 2022 -- can't compile assertion with the spaceship operator
+
+[The C++ standard requires that `std::foo_ordering` is only comparable with
+a literal 0](https://eel.is/c++draft/cmp#categories.pre-3). There are
+multiple strategies a stdlib implementation can take to achieve this, and
+MSVC's STL has changed the strategy they use between two releases of VS 2022.
+
+With the new strategy, `REQUIRE((a <=> b) == 0)` no longer compiles under
+MSVC. Note that Catch2 can compile code using MSVC STL's new strategy,
+but only when compiled with a C++20 conforming compiler. MSVC is currently
+not conformant enough, but `clang-cl` will compile the assertion above
+using MSVC STL without problem.
+
+This change got in with MSVC v19.37](https://godbolt.org/z/KG9obzdvE).
+

docs/logging.md

@@ -114,6 +114,10 @@ Similar to `INFO`, but messages are not limited to their own scope: They are rem
 
 The message is always reported but does not fail the test.
 
+**SUCCEED(** _message expression_ **)**
+
+The message is reported and the test case succeeds.
+
 **FAIL(** _message expression_ **)**
 
 The message is reported and the test case fails.

docs/release-notes.md

@@ -2,6 +2,8 @@
 
 # Release notes
 **Contents**<br>
+[3.5.4](#354)<br>
+[3.5.3](#353)<br>
 [3.5.2](#352)<br>
 [3.5.1](#351)<br>
 [3.5.0](#350)<br>
@@ -60,7 +62,55 @@
 [Even Older versions](#even-older-versions)<br>
 
 
-## 3.5.1
+## 3.5.4
+
+### Fixes
+* Fixed potential compilation error when asked to generate random integers whose type did not match `std::(u)int*_t`.
+  * This manifested itself when generating random `size_t`s on MacOS
+* Added missing outlined destructor causing `Wdelete-incomplete` when compiling against libstdc++ in C++23 mode (#2852)
+* Fixed regression where decomposing assertion with const instance of `std::foo_ordering` would not compile
+
+### Improvements
+* Reintroduced support for GCC 5 and 6 (#2836)
+  * As with VS2017, if they start causing trouble again, they will be dropped again.
+* Added workaround for targetting newest MacOS (Sonoma) using GCC (#2837, #2839)
+* `CATCH_CONFIG_DEFAULT_REPORTER` can now be an arbitrary reporter spec
+  * Previously it could only be a plain reporter name, so it was impossible to compile in custom arguments to the reporter.
+* Improved performance of generating 64bit random integers by 20+%
+
+### Miscellaneous
+* Significantly improved Conan in-tree recipe (#2831)
+* `DL_PATHS` in `catch_discover_tests` now supports multiple arguments (#2852, #2736)
+* Fixed preprocessor logic for checking whether we expect reproducible floating point results in tests.
+* Improved the floating point tests structure to avoid `Wunused` when the reproducibility tests are disabled (#2845)
+
+
+## 3.5.3
+
+### Fixes
+* Fixed OOB access when computing filename tag (from the `-#` flag) for file without extension (#2798)
+* Fixed the linking against `log` on Android to be `PRIVATE` (#2815)
+* Fixed `Wuseless-cast` in benchmarking internals (#2823)
+
+### Improvements
+* Restored compatibility with VS2017 (#2792, #2822)
+  * The baseline for Catch2 is still C++14 with some reasonable workarounds for specific compilers, so if VS2017 starts acting up again, the support will be dropped again.
+* Suppressed clang-tidy's `bugprone-chained-comparison` in assertions (#2801)
+* Improved the static analysis mode to evaluate arguments to `TEST_CASE` and `SECTION` (#2817)
+  * Clang-tidy should no longer warn about runtime arguments to these macros being unused in static analysis mode.
+  * Clang-tidy can warn on issues involved arguments to these macros.
+* Added support for literal-zero detectors based on `consteval` constructors
+  * This is required for compiling `REQUIRE((a <=> b) == 0)` against MSVC's stdlib.
+  * Sadly, MSVC still cannot compile this assertion as it does not implement C++20 correctly.
+  * You can use `clang-cl` with MSVC's stdlib instead.
+  * If for some godforsaken reasons you want to understand this better, read the two relevant commits: [`dc51386b9fd61f99ea9c660d01867e6ad489b403`](https://github.com/catchorg/Catch2/commit/dc51386b9fd61f99ea9c660d01867e6ad489b403), and [`0787132fc82a75e3fb255aa9484ca1dc1eff2a30`](https://github.com/catchorg/Catch2/commit/0787132fc82a75e3fb255aa9484ca1dc1eff2a30).
+
+### Miscellaneous
+* Disabled tests for FP random generator reproducibility on non-SSE2 x86 targets (#2796)
+* Modified the in-tree Conan recipe to support Conan 2 (#2805)
+
+
+## 3.5.2
 
 ### Fixes
 * Fixed `-Wsubobject-linkage` in the Console reporter (#2794)

docs/reporters.md

@@ -5,7 +5,7 @@ Reporters are a customization point for most of Catch2's output, e.g.
 formatting and writing out [assertions (whether passing or failing),
 sections, test cases, benchmarks, and so on](reporter-events.md#top).
 
-Catch2 comes with a bunch of reporters by default (currently 8), and
+Catch2 comes with a bunch of reporters by default (currently 9), and
 you can also write your own reporter. Because multiple reporters can
 be active at the same time, your own reporters do not even have to handle
 all reporter event, just the ones you are interested in, e.g. benchmarks.

docs/tutorial.md

@@ -16,7 +16,7 @@ Ideally you should be using Catch2 through its [CMake integration](cmake-integra
 Catch2 also provides pkg-config files and two file (header + cpp)
 distribution, but this documentation will assume you are using CMake. If
 you are using the two file distribution instead, remember to replace
-the included header with `catch_amalgamated.hpp`.
+the included header with `catch_amalgamated.hpp` ([step by step instructions](migrate-v2-to-v3.md#how-to-migrate-projects-from-v2-to-v3)).
 
 
 ## Writing tests

examples/210-Evt-EventListeners.cpp

@@ -385,8 +385,7 @@ struct MyListener : Catch::EventListenerBase {
 CATCH_REGISTER_LISTENER( MyListener )
 
 // Get rid of Wweak-tables
-MyListener::~MyListener() {}
-
+MyListener::~MyListener() = default;
 
 // -----------------------------------------------------------------------
 // 3. Test cases:

examples/231-Cfg-OutputStreams.cpp

@@ -22,7 +22,7 @@ class out_buff : public std::stringbuf {
     std::FILE* m_stream;
 public:
     out_buff(std::FILE* stream):m_stream(stream) {}
-    ~out_buff();
+    ~out_buff() override;
     int sync() override {
         int ret = 0;
         for (unsigned char c : str()) {

examples/232-Cfg-CustomMain.cpp

@@ -35,7 +35,7 @@ int main(int argc, char** argv) {
       return returnCode;
 
   // if set on the command line then 'height' is now set at this point
-  std::cout << "height: " << height << std::endl;
+  std::cout << "height: " << height << '\n';
 
   return session.run();
 }

examples/300-Gen-OwnGenerator.cpp

@@ -21,7 +21,7 @@
 namespace {
 
 // This class shows how to implement a simple generator for Catch tests
-class RandomIntGenerator : public Catch::Generators::IGenerator<int> {
+class RandomIntGenerator final : public Catch::Generators::IGenerator<int> {
     std::minstd_rand m_rand;
     std::uniform_int_distribution<> m_dist;
     int current_number;

examples/301-Gen-MapTypeConversion.cpp

@@ -24,12 +24,12 @@ namespace {
 // Returns a line from a stream. You could have it e.g. read lines from
 // a file, but to avoid problems with paths in examples, we will use
 // a fixed stringstream.
-class LineGenerator : public Catch::Generators::IGenerator<std::string> {
+class LineGenerator final : public Catch::Generators::IGenerator<std::string> {
     std::string m_line;
     std::stringstream m_stream;
 public:
-    LineGenerator() {
-        m_stream.str("1\n2\n3\n4\n");
+    explicit LineGenerator( std::string const& lines ) {
+        m_stream.str( lines );
         if (!next()) {
             Catch::Generators::Detail::throw_generator_exception("Couldn't read a single line");
         }
@@ -49,18 +49,19 @@ std::string const& LineGenerator::get() const {
 // This helper function provides a nicer UX when instantiating the generator
 // Notice that it returns an instance of GeneratorWrapper<std::string>, which
 // is a value-wrapper around std::unique_ptr<IGenerator<std::string>>.
-Catch::Generators::GeneratorWrapper<std::string> lines(std::string /* ignored for example */) {
+Catch::Generators::GeneratorWrapper<std::string>
+lines( std::string const& lines ) {
     return Catch::Generators::GeneratorWrapper<std::string>(
-        new LineGenerator()
-    );
+        new LineGenerator( lines ) );
 }
 
 } // end anonymous namespace
 
 
 TEST_CASE("filter can convert types inside the generator expression", "[example][generator]") {
-    auto num = GENERATE(map<int>([](std::string const& line) { return std::stoi(line); },
-                                 lines("fake-file")));
+    auto num = GENERATE(
+        map<int>( []( std::string const& line ) { return std::stoi( line ); },
+                  lines( "1\n2\n3\n4\n" ) ) );
 
     REQUIRE(num > 0);
 }

extras/CatchAddTests.cmake

@@ -21,8 +21,8 @@ function(catch_discover_tests_impl)
   cmake_parse_arguments(
     ""
     ""
-    "TEST_EXECUTABLE;TEST_WORKING_DIR;TEST_DL_PATHS;TEST_OUTPUT_DIR;TEST_OUTPUT_PREFIX;TEST_OUTPUT_SUFFIX;TEST_PREFIX;TEST_REPORTER;TEST_SPEC;TEST_SUFFIX;TEST_LIST;CTEST_FILE"
-    "TEST_EXTRA_ARGS;TEST_PROPERTIES;TEST_EXECUTOR"
+    "TEST_EXECUTABLE;TEST_WORKING_DIR;TEST_OUTPUT_DIR;TEST_OUTPUT_PREFIX;TEST_OUTPUT_SUFFIX;TEST_PREFIX;TEST_REPORTER;TEST_SPEC;TEST_SUFFIX;TEST_LIST;CTEST_FILE"
+    "TEST_EXTRA_ARGS;TEST_PROPERTIES;TEST_EXECUTOR;TEST_DL_PATHS"
     ${ARGN}
   )
 

extras/ParseAndAddCatchTests.cmake

@@ -187,7 +187,7 @@ function(ParseAndAddCatchTests_ParseFile SourceFile TestTarget)
             if(result)
                 set(HiddenTagFound ON)
                 break()
-            endif(result)
+            endif()
         endforeach(label)
         if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_LESS "3.9")
             ParseAndAddCatchTests_PrintDebugMessage("Skipping test \"${CTestName}\" as it has [!hide], [.] or [.foo] label")

extras/catch_amalgamated.cpp

@@ -6,8 +6,8 @@
 
 // SPDX-License-Identifier: BSL-1.0
 
-//  Catch v3.5.2
-//  Generated: 2024-01-15 14:06:36.675713
+//  Catch v3.5.4
+//  Generated: 2024-04-10 12:03:46.281848
 //  ----------------------------------------------------------
 //  This file is an amalgamation of multiple different files.
 //  You probably shouldn't edit it directly.
@@ -101,8 +101,8 @@ namespace Catch {
                     FDuration mean = FDuration(0);
                     int i = 0;
                     for (auto it = first; it < last; ++it, ++i) {
-                        samples.push_back(FDuration(*it));
-                        mean += FDuration(*it);
+                        samples.push_back(*it);
+                        mean += *it;
                     }
                     mean /= i;
 
@@ -187,7 +187,7 @@ namespace Catch {
                           double const* last,
                           Estimator& estimator ) {
                     auto n = static_cast<size_t>( last - first );
-                    std::uniform_int_distribution<size_t> dist( 0, n - 1 );
+                    Catch::uniform_integer_distribution<size_t> dist( 0, n - 1 );
 
                     sample out;
                     out.reserve( resamples );
@@ -558,7 +558,7 @@ bool marginComparison(double lhs, double rhs, double margin) {
 namespace Catch {
 
     Approx::Approx ( double value )
-    :   m_epsilon( std::numeric_limits<float>::epsilon()*100. ),
+    :   m_epsilon( static_cast<double>(std::numeric_limits<float>::epsilon())*100. ),
         m_margin( 0.0 ),
         m_scale( 0.0 ),
         m_value( value )
@@ -807,14 +807,16 @@ namespace Catch {
 
         // Insert the default reporter if user hasn't asked for a specific one
         if ( m_data.reporterSpecifications.empty() ) {
-            m_data.reporterSpecifications.push_back( {
 #if defined( CATCH_CONFIG_DEFAULT_REPORTER )
-                CATCH_CONFIG_DEFAULT_REPORTER,
+            const auto default_spec = CATCH_CONFIG_DEFAULT_REPORTER;
 #else
-                "console",
+            const auto default_spec = "console";
 #endif
-                {}, {}, {}
-            } );
+            auto parsed = parseReporterSpec(default_spec);
+            CATCH_ENFORCE( parsed,
+                           "Cannot parse the provided default reporter spec: '"
+                               << default_spec << '\'' );
+            m_data.reporterSpecifications.push_back( std::move( *parsed ) );
         }
 
         if ( enableBazelEnvSupport() ) {
@@ -1038,6 +1040,7 @@ namespace Catch {
                     m_messages.back().message += " := ";
                     start = pos;
                 }
+            default:; // noop
             }
         }
         assert(openings.empty() && "Mismatched openings");
@@ -1581,8 +1584,10 @@ namespace Catch {
             while (lastDot > 0 && filename[lastDot - 1] != '.') {
                 --lastDot;
             }
-            --lastDot;
+            // In theory we could have filename without any extension in it
+            if ( lastDot == 0 ) { return StringRef(); }
 
+            --lastDot;
             size_t nameStart = lastDot;
             while (nameStart > 0 && filename[nameStart - 1] != '/' && filename[nameStart - 1] != '\\') {
                 --nameStart;
@@ -1966,13 +1971,13 @@ namespace Detail {
         }
     } // end unnamed namespace
 
-    std::string convertIntoString(StringRef string, bool escape_invisibles) {
+    std::string convertIntoString(StringRef string, bool escapeInvisibles) {
         std::string ret;
         // This is enough for the "don't escape invisibles" case, and a good
         // lower bound on the "escape invisibles" case.
         ret.reserve(string.size() + 2);
 
-        if (!escape_invisibles) {
+        if (!escapeInvisibles) {
             ret += '"';
             ret += string;
             ret += '"';
@@ -2050,7 +2055,7 @@ std::string StringMaker<char const*>::convert(char const* str) {
         return{ "{null string}" };
     }
 }
-std::string StringMaker<char*>::convert(char* str) {
+std::string StringMaker<char*>::convert(char* str) { // NOLINT(readability-non-const-parameter)
     if (str) {
         return Detail::convertIntoString( str );
     } else {
@@ -2147,8 +2152,8 @@ std::string StringMaker<signed char>::convert(signed char value) {
 std::string StringMaker<char>::convert(char c) {
     return ::Catch::Detail::stringify(static_cast<signed char>(c));
 }
-std::string StringMaker<unsigned char>::convert(unsigned char c) {
-    return ::Catch::Detail::stringify(static_cast<char>(c));
+std::string StringMaker<unsigned char>::convert(unsigned char value) {
+    return ::Catch::Detail::stringify(static_cast<char>(value));
 }
 
 int StringMaker<float>::precision = 5;
@@ -2268,7 +2273,7 @@ namespace Catch {
     }
 
     Version const& libraryVersion() {
-        static Version version( 3, 5, 2, "", 0 );
+        static Version version( 3, 5, 4, "", 0 );
         return version;
     }
 
@@ -3092,7 +3097,7 @@ namespace Catch {
                     line = trim(line);
                     if( !line.empty() && !startsWith( line, '#' ) ) {
                         if( !startsWith( line, '"' ) )
-                            line = '"' + line + '"';
+                            line = '"' + CATCH_MOVE(line) + '"';
                         config.testsOrTags.push_back( line );
                         config.testsOrTags.emplace_back( "," );
                     }
@@ -3573,21 +3578,21 @@ namespace {
 
 namespace Catch {
 
-    Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode implSelection,
+    Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode colourSelection,
                                                    IStream* stream ) {
 #if defined( CATCH_CONFIG_COLOUR_WIN32 )
-        if ( implSelection == ColourMode::Win32 ) {
+        if ( colourSelection == ColourMode::Win32 ) {
             return Detail::make_unique<Win32ColourImpl>( stream );
         }
 #endif
-        if ( implSelection == ColourMode::ANSI ) {
+        if ( colourSelection == ColourMode::ANSI ) {
             return Detail::make_unique<ANSIColourImpl>( stream );
         }
-        if ( implSelection == ColourMode::None ) {
+        if ( colourSelection == ColourMode::None ) {
             return Detail::make_unique<NoColourImpl>( stream );
         }
 
-        if ( implSelection == ColourMode::PlatformDefault) {
+        if ( colourSelection == ColourMode::PlatformDefault) {
 #if defined( CATCH_CONFIG_COLOUR_WIN32 )
             if ( Win32ColourImpl::useImplementationForStream( *stream ) ) {
                 return Detail::make_unique<Win32ColourImpl>( stream );
@@ -3599,7 +3604,7 @@ namespace Catch {
             return Detail::make_unique<NoColourImpl>( stream );
         }
 
-        CATCH_ERROR( "Could not create colour impl for selection " << static_cast<int>(implSelection) );
+        CATCH_ERROR( "Could not create colour impl for selection " << static_cast<int>(colourSelection) );
     }
 
     bool isColourImplAvailable( ColourMode colourSelection ) {
@@ -3807,7 +3812,12 @@ namespace Catch {
 
 namespace Catch {
 
-    ITransientExpression::~ITransientExpression() = default;
+    void ITransientExpression::streamReconstructedExpression(
+        std::ostream& os ) const {
+        // We can't make this function pure virtual to keep ITransientExpression
+        // constexpr, so we write error message instead
+        os << "Some class derived from ITransientExpression without overriding streamReconstructedExpression";
+    }
 
     void formatReconstructedExpression( std::ostream &os, std::string const& lhs, StringRef op, std::string const& rhs ) {
         if( lhs.size() + rhs.size() < 40 &&
@@ -4473,7 +4483,7 @@ namespace Catch {
         m_os{ os }, m_indent_level{ indent_level } {
         m_os << '{';
     }
-    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ):
+    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ) noexcept:
         m_os{ source.m_os },
         m_indent_level{ source.m_indent_level },
         m_should_comma{ source.m_should_comma },
@@ -4504,7 +4514,7 @@ namespace Catch {
         m_os{ os }, m_indent_level{ indent_level } {
         m_os << '[';
     }
-    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ):
+    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ) noexcept:
         m_os{ source.m_os },
         m_indent_level{ source.m_indent_level },
         m_should_comma{ source.m_should_comma },
@@ -5283,7 +5293,7 @@ namespace Catch {
             auto kv = splitKVPair( parts[i] );
             auto key = kv.key, value = kv.value;
 
-            if ( key.empty() || value.empty() ) {
+            if ( key.empty() || value.empty() ) { // NOLINT(bugprone-branch-clone)
                 return {};
             } else if ( key[0] == 'X' ) {
                 // This is a reporter-specific option, we don't check these
@@ -6297,17 +6307,29 @@ namespace Catch {
     }
 
     bool replaceInPlace( std::string& str, std::string const& replaceThis, std::string const& withThis ) {
-        bool replaced = false;
         std::size_t i = str.find( replaceThis );
-        while( i != std::string::npos ) {
-            replaced = true;
-            str = str.substr( 0, i ) + withThis + str.substr( i+replaceThis.size() );
-            if( i < str.size()-withThis.size() )
-                i = str.find( replaceThis, i+withThis.size() );
+        if (i == std::string::npos) {
+            return false;
+        }
+        std::size_t copyBegin = 0;
+        std::string origStr = CATCH_MOVE(str);
+        str.clear();
+        // There is at least one replacement, so reserve with the best guess
+        // we can make without actually counting the number of occurences.
+        str.reserve(origStr.size() - replaceThis.size() + withThis.size());
+        do {
+            str.append(origStr, copyBegin, i-copyBegin );
+            str += withThis;
+            copyBegin = i + replaceThis.size();
+            if( copyBegin < origStr.size() )
+                i = origStr.find( replaceThis, copyBegin );
             else
                 i = std::string::npos;
+        } while( i != std::string::npos );
+        if ( copyBegin < origStr.size() ) {
+            str.append(origStr, copyBegin, origStr.size() );
         }
-        return replaced;
+        return true;
     }
 
     std::vector<StringRef> splitStringRef( StringRef str, char delimiter ) {
@@ -6581,6 +6603,8 @@ namespace Catch {
         return getRegistryHub().getTestCaseRegistry().getAllTestsSorted( config );
     }
 
+    TestRegistry::~TestRegistry() = default;
+
     void TestRegistry::registerTest(Detail::unique_ptr<TestCaseInfo> testInfo, Detail::unique_ptr<ITestInvoker> testInvoker) {
         m_handles.emplace_back(testInfo.get(), testInvoker.get());
         m_viewed_test_infos.push_back(testInfo.get());
@@ -9099,8 +9123,8 @@ void ConsoleReporter::testRunEnded(TestRunStats const& _testRunStats) {
     m_stream << '\n' << std::flush;
     StreamingReporterBase::testRunEnded(_testRunStats);
 }
-void ConsoleReporter::testRunStarting(TestRunInfo const& _testInfo) {
-    StreamingReporterBase::testRunStarting(_testInfo);
+void ConsoleReporter::testRunStarting(TestRunInfo const& _testRunInfo) {
+    StreamingReporterBase::testRunStarting(_testRunInfo);
     if ( m_config->testSpec().hasFilters() ) {
         m_stream << m_colour->guardColour( Colour::BrightYellow ) << "Filters: "
                  << m_config->testSpec() << '\n';
@@ -9253,8 +9277,7 @@ namespace Catch {
     namespace {
         struct BySectionInfo {
             BySectionInfo( SectionInfo const& other ): m_other( other ) {}
-            BySectionInfo( BySectionInfo const& other ):
-                m_other( other.m_other ) {}
+            BySectionInfo( BySectionInfo const& other ) = default;
             bool operator()(
                 Detail::unique_ptr<CumulativeReporterBase::SectionNode> const&
                     node ) const {
@@ -9879,8 +9902,8 @@ namespace Catch {
         return "Outputs listings as JSON. Test listing is Work-in-Progress!";
     }
 
-    void JsonReporter::testRunStarting( TestRunInfo const& testInfo ) {
-        StreamingReporterBase::testRunStarting( testInfo );
+    void JsonReporter::testRunStarting( TestRunInfo const& runInfo ) {
+        StreamingReporterBase::testRunStarting( runInfo );
         endListing();
 
         assert( isInside( Writer::Object ) );
@@ -10178,7 +10201,7 @@ namespace Catch {
 
         static void normalizeNamespaceMarkers(std::string& str) {
             std::size_t pos = str.find( "::" );
-            while ( pos != str.npos ) {
+            while ( pos != std::string::npos ) {
                 str.replace( pos, 2, "." );
                 pos += 1;
                 pos = str.find( "::", pos );

extras/catch_amalgamated.hpp

@@ -6,8 +6,8 @@
 
 // SPDX-License-Identifier: BSL-1.0
 
-//  Catch v3.5.2
-//  Generated: 2024-01-15 14:06:34.036475
+//  Catch v3.5.4
+//  Generated: 2024-04-10 12:03:45.785902
 //  ----------------------------------------------------------
 //  This file is an amalgamation of multiple different files.
 //  You probably shouldn't edit it directly.
@@ -87,6 +87,9 @@
 // See e.g.:
 // https://opensource.apple.com/source/CarbonHeaders/CarbonHeaders-18.1/TargetConditionals.h.auto.html
 #ifdef __APPLE__
+#  ifndef __has_extension
+#    define __has_extension(x) 0
+#  endif
 #  include <TargetConditionals.h>
 #  if (defined(TARGET_OS_OSX) && TARGET_OS_OSX == 1) || \
       (defined(TARGET_OS_MAC) && TARGET_OS_MAC == 1)
@@ -114,14 +117,14 @@
 
 #ifdef __cplusplus
 
-#  if (__cplusplus >= 201402L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 201402L)
-#    define CATCH_CPP14_OR_GREATER
-#  endif
-
 #  if (__cplusplus >= 201703L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
 #    define CATCH_CPP17_OR_GREATER
 #  endif
 
+#  if (__cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
+#    define CATCH_CPP20_OR_GREATER
+#  endif
+
 #endif
 
 // Only GCC compiler should be used in this block, so other compilers trying to
@@ -762,8 +765,8 @@ namespace Catch {
         constexpr const_iterator end() const { return m_start + m_size; }
 
 
-        friend std::string& operator += (std::string& lhs, StringRef sr);
-        friend std::ostream& operator << (std::ostream& os, StringRef sr);
+        friend std::string& operator += (std::string& lhs, StringRef rhs);
+        friend std::ostream& operator << (std::ostream& os, StringRef str);
         friend std::string operator+(StringRef lhs, StringRef rhs);
 
         /**
@@ -2696,11 +2699,11 @@ namespace Catch {
     };
     template<>
     struct StringMaker<signed char> {
-        static std::string convert(signed char c);
+        static std::string convert(signed char value);
     };
     template<>
     struct StringMaker<unsigned char> {
-        static std::string convert(unsigned char c);
+        static std::string convert(unsigned char value);
     };
 
     template<>
@@ -5147,6 +5150,86 @@ namespace Detail {
 #include <type_traits>
 #include <iosfwd>
 
+/** \file
+ * Why does decomposing look the way it does:
+ *
+ * Conceptually, decomposing is simple. We change `REQUIRE( a == b )` into
+ * `Decomposer{} <= a == b`, so that `Decomposer{} <= a` is evaluated first,
+ * and our custom operator is used for `a == b`, because `a` is transformed
+ * into `ExprLhs<T&>` and then into `BinaryExpr<T&, U&>`.
+ *
+ * In practice, decomposing ends up a mess, because we have to support
+ * various fun things.
+ *
+ * 1) Types that are only comparable with literal 0, and they do this by
+ *    comparing against a magic type with pointer constructor and deleted
+ *    other constructors. Example: `REQUIRE((a <=> b) == 0)` in libstdc++
+ *
+ * 2) Types that are only comparable with literal 0, and they do this by
+ *    comparing against a magic type with consteval integer constructor.
+ *    Example: `REQUIRE((a <=> b) == 0)` in current MSVC STL.
+ *
+ * 3) Types that have no linkage, and so we cannot form a reference to
+ *    them. Example: some implementations of traits.
+ *
+ * 4) Starting with C++20, when the compiler sees `a == b`, it also uses
+ *    `b == a` when constructing the overload set. For us this means that
+ *    when the compiler handles `ExprLhs<T> == b`, it also tries to resolve
+ *    the overload set for `b == ExprLhs<T>`.
+ *
+ * To accomodate these use cases, decomposer ended up rather complex.
+ *
+ * 1) These types are handled by adding SFINAE overloads to our comparison
+ *    operators, checking whether `T == U` are comparable with the given
+ *    operator, and if not, whether T (or U) are comparable with literal 0.
+ *    If yes, the overload compares T (or U) with 0 literal inline in the
+ *    definition.
+ *
+ *    Note that for extra correctness, we check  that the other type is
+ *    either an `int` (literal 0 is captured as `int` by templates), or
+ *    a `long` (some platforms use 0L for `NULL` and we want to support
+ *    that for pointer comparisons).
+ *
+ * 2) For these types, `is_foo_comparable<T, int>` is true, but letting
+ *    them fall into the overload that actually does `T == int` causes
+ *    compilation error. Handling them requires that the decomposition
+ *    is `constexpr`, so that P2564R3 applies and the `consteval` from
+ *    their accompanying magic type is propagated through the `constexpr`
+ *    call stack.
+ *
+ *    However this is not enough to handle these types automatically,
+ *    because our default is to capture types by reference, to avoid
+ *    runtime copies. While these references cannot become dangling,
+ *    they outlive the constexpr context and thus the default capture
+ *    path cannot be actually constexpr.
+ *
+ *    The solution is to capture these types by value, by explicitly
+ *    specializing `Catch::capture_by_value` for them. Catch2 provides
+ *    specialization for `std::foo_ordering`s, but users can specialize
+ *    the trait for their own types as well.
+ *
+ * 3) If a type has no linkage, we also cannot capture it by reference.
+ *    The solution is once again to capture them by value. We handle
+ *    the common cases by using `std::is_arithmetic` as the default
+ *    for `Catch::capture_by_value`, but that is only a some-effort
+ *    heuristic. But as with 2), users can specialize `capture_by_value`
+ *    for their own types as needed.
+ *
+ * 4) To support C++20 and make the SFINAE on our decomposing operators
+ *    work, the SFINAE has to happen in return type, rather than in
+ *    a template type. This is due to our use of logical type traits
+ *    (`conjunction`/`disjunction`/`negation`), that we use to workaround
+ *    an issue in older (9-) versions of GCC. I still blame C++20 for
+ *    this, because without the comparison order switching, the logical
+ *    traits could still be used in template type.
+ *
+ * There are also other side concerns, e.g. supporting both `REQUIRE(a)`
+ * and `REQUIRE(a == b)`, or making `REQUIRE_THAT(a, IsEqual(b))` slot
+ * nicely into the same expression handling logic, but these are rather
+ * straightforward and add only a bit of complexity (e.g. common base
+ * class for decomposed expressions).
+ */
+
 #ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable:4389) // '==' : signed/unsigned mismatch
@@ -5164,8 +5247,39 @@ namespace Detail {
 #  pragma GCC diagnostic ignored "-Wsign-compare"
 #endif
 
+#if defined(CATCH_CPP20_OR_GREATER) && __has_include(<compare>)
+#  include <compare>
+#    if defined( __cpp_lib_three_way_comparison ) && \
+            __cpp_lib_three_way_comparison >= 201907L
+#      define CATCH_CONFIG_CPP20_COMPARE_OVERLOADS
+#    endif
+#endif
+
 namespace Catch {
 
+    namespace Detail {
+        // This was added in C++20, but we require only C++14 for now.
+        template <typename T>
+        using RemoveCVRef_t = std::remove_cv_t<std::remove_reference_t<T>>;
+    }
+
+    // Note: There is nothing that stops us from extending this,
+    //       e.g. to `std::is_scalar`, but the more encompassing
+    //       traits are usually also more expensive. For now we
+    //       keep this as it used to be and it can be changed later.
+    template <typename T>
+    struct capture_by_value
+        : std::integral_constant<bool, std::is_arithmetic<T>{}> {};
+
+#if defined( CATCH_CONFIG_CPP20_COMPARE_OVERLOADS )
+    template <>
+    struct capture_by_value<std::strong_ordering> : std::true_type {};
+    template <>
+    struct capture_by_value<std::weak_ordering> : std::true_type {};
+    template <>
+    struct capture_by_value<std::partial_ordering> : std::true_type {};
+#endif
+
     template <typename T>
     struct always_false : std::false_type {};
 
@@ -5174,11 +5288,12 @@ namespace Catch {
         bool m_result;
 
     public:
-        auto isBinaryExpression() const -> bool { return m_isBinaryExpression; }
-        auto getResult() const -> bool { return m_result; }
-        virtual void streamReconstructedExpression( std::ostream &os ) const = 0;
+        constexpr auto isBinaryExpression() const -> bool { return m_isBinaryExpression; }
+        constexpr auto getResult() const -> bool { return m_result; }
+        //! This function **has** to be overriden by the derived class.
+        virtual void streamReconstructedExpression( std::ostream& os ) const;
 
-        ITransientExpression( bool isBinaryExpression, bool result )
+        constexpr ITransientExpression( bool isBinaryExpression, bool result )
         :   m_isBinaryExpression( isBinaryExpression ),
             m_result( result )
         {}
@@ -5187,14 +5302,13 @@ namespace Catch {
         ITransientExpression(ITransientExpression const&) = default;
         ITransientExpression& operator=(ITransientExpression const&) = default;
 
-        // We don't actually need a virtual destructor, but many static analysers
-        // complain if it's not here :-(
-        virtual ~ITransientExpression(); // = default;
-
         friend std::ostream& operator<<(std::ostream& out, ITransientExpression const& expr) {
             expr.streamReconstructedExpression(out);
             return out;
         }
+
+    protected:
+        ~ITransientExpression() = default;
     };
 
     void formatReconstructedExpression( std::ostream &os, std::string const& lhs, StringRef op, std::string const& rhs );
@@ -5211,7 +5325,7 @@ namespace Catch {
         }
 
     public:
-        BinaryExpr( bool comparisonResult, LhsT lhs, StringRef op, RhsT rhs )
+        constexpr BinaryExpr( bool comparisonResult, LhsT lhs, StringRef op, RhsT rhs )
         :   ITransientExpression{ true, comparisonResult },
             m_lhs( lhs ),
             m_op( op ),
@@ -5284,7 +5398,7 @@ namespace Catch {
         }
 
     public:
-        explicit UnaryExpr( LhsT lhs )
+        explicit constexpr UnaryExpr( LhsT lhs )
         :   ITransientExpression{ false, static_cast<bool>(lhs) },
             m_lhs( lhs )
         {}
@@ -5295,31 +5409,31 @@ namespace Catch {
     class ExprLhs {
         LhsT m_lhs;
     public:
-        explicit ExprLhs( LhsT lhs ) : m_lhs( lhs ) {}
+        explicit constexpr ExprLhs( LhsT lhs ) : m_lhs( lhs ) {}
 
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR( id, op )           \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                Detail::negation<std::is_arithmetic<           \
-                                    std::remove_reference_t<RhsT>>>>::value,   \
+                                Detail::negation<capture_by_value<             \
+                                    Detail::RemoveCVRef_t<RhsT>>>>::value,     \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                std::is_arithmetic<RhsT>>::value,              \
+                                capture_by_value<RhsT>>::value,                \
             BinaryExpr<LhsT, RhsT>> {                                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_eq_0_comparable<LhsT>,                              \
@@ -5332,8 +5446,8 @@ namespace Catch {
             static_cast<bool>( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs };   \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_eq_0_comparable<RhsT>,                              \
@@ -5350,29 +5464,30 @@ namespace Catch {
 
     #undef CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR
 
+
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( id, op )         \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                Detail::negation<std::is_arithmetic<           \
-                                    std::remove_reference_t<RhsT>>>>::value,   \
+                                Detail::negation<capture_by_value<             \
+                                    Detail::RemoveCVRef_t<RhsT>>>>::value,     \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                std::is_arithmetic<RhsT>>::value,              \
+                                capture_by_value<RhsT>>::value,                \
             BinaryExpr<LhsT, RhsT>> {                                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_##id##_0_comparable<LhsT>,                          \
@@ -5383,8 +5498,8 @@ namespace Catch {
             static_cast<bool>( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs };   \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_##id##_0_comparable<RhsT>,                          \
@@ -5404,17 +5519,17 @@ namespace Catch {
 
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR( op )                        \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
-            !std::is_arithmetic<std::remove_reference_t<RhsT>>::value,         \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
+            !capture_by_value<Detail::RemoveCVRef_t<RhsT>>::value,             \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<std::is_arithmetic<RhsT>::value,                    \
-                           BinaryExpr<LhsT, RhsT>> {                           \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<capture_by_value<RhsT>::value,                     \
+                            BinaryExpr<LhsT, RhsT>> {                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }
@@ -5439,19 +5554,22 @@ namespace Catch {
             "wrap the expression inside parentheses, or decompose it");
         }
 
-        auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
+        constexpr auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
             return UnaryExpr<LhsT>{ m_lhs };
         }
     };
 
     struct Decomposer {
-        template<typename T, std::enable_if_t<!std::is_arithmetic<std::remove_reference_t<T>>::value, int> = 0>
-        friend auto operator <= ( Decomposer &&, T && lhs ) -> ExprLhs<T const&> {
+        template <typename T,
+                  std::enable_if_t<!capture_by_value<Detail::RemoveCVRef_t<T>>::value,
+                      int> = 0>
+        constexpr friend auto operator <= ( Decomposer &&, T && lhs ) -> ExprLhs<T const&> {
             return ExprLhs<const T&>{ lhs };
         }
 
-        template<typename T, std::enable_if_t<std::is_arithmetic<T>::value, int> = 0>
-        friend auto operator <= ( Decomposer &&, T value ) -> ExprLhs<T> {
+        template <typename T,
+                  std::enable_if_t<capture_by_value<T>::value, int> = 0>
+        constexpr friend auto operator <= ( Decomposer &&, T value ) -> ExprLhs<T> {
             return ExprLhs<T>{ value };
         }
     };
@@ -5571,7 +5689,7 @@ namespace Catch {
         INTERNAL_CATCH_TRY { \
             CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
             CATCH_INTERNAL_SUPPRESS_PARENTHESES_WARNINGS \
-            catchAssertionHandler.handleExpr( Catch::Decomposer() <= __VA_ARGS__ ); \
+            catchAssertionHandler.handleExpr( Catch::Decomposer() <= __VA_ARGS__ ); /* NOLINT(bugprone-chained-comparison) */ \
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION \
         } INTERNAL_CATCH_CATCH( catchAssertionHandler ) \
         INTERNAL_CATCH_REACT( catchAssertionHandler ) \
@@ -5786,7 +5904,9 @@ namespace Catch {
     namespace Detail {
         // Intentionally without linkage, as it should only be used as a dummy
         // symbol for static analysis.
-        int GetNewSectionHint();
+        // The arguments are used as a dummy for checking warnings in the passed
+        // expressions.
+        int GetNewSectionHint( StringRef, const char* const = nullptr );
     } // namespace Detail
 } // namespace Catch
 
@@ -5797,7 +5917,8 @@ namespace Catch {
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
         if ( [[maybe_unused]] const int catchInternalPreviousSectionHint =  \
                  catchInternalSectionHint,                                  \
-             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalSectionHint =                                     \
+                 Catch::Detail::GetNewSectionHint(__VA_ARGS__);             \
              catchInternalPreviousSectionHint == __LINE__ )                 \
         CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 
@@ -5807,7 +5928,8 @@ namespace Catch {
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
         if ( [[maybe_unused]] const int catchInternalPreviousSectionHint =  \
                  catchInternalSectionHint,                                  \
-             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(   \
+                ( Catch::ReusableStringStream() << __VA_ARGS__ ).str());    \
              catchInternalPreviousSectionHint == __LINE__ )                 \
         CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 
@@ -5929,7 +6051,7 @@ struct AutoReg : Detail::NonCopyable {
 namespace Catch {
     namespace Detail {
         struct DummyUse {
-            DummyUse( void ( * )( int ) );
+            DummyUse( void ( * )( int ), Catch::NameAndTags const& );
         };
     } // namespace Detail
 } // namespace Catch
@@ -5941,18 +6063,18 @@ namespace Catch {
 // tests can compile. The redefined `TEST_CASE` shadows this with param.
 static int catchInternalSectionHint = 0;
 
-#    define INTERNAL_CATCH_TESTCASE2( fname )                              \
+#    define INTERNAL_CATCH_TESTCASE2( fname, ... )                         \
         static void fname( int );                                          \
         CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                          \
         CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS                           \
         CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                   \
         static const Catch::Detail::DummyUse INTERNAL_CATCH_UNIQUE_NAME(   \
-            dummyUser )( &(fname) );                                       \
+            dummyUser )( &(fname), Catch::NameAndTags{ __VA_ARGS__ } );    \
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                            \
         static void fname( [[maybe_unused]] int catchInternalSectionHint ) \
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 #    define INTERNAL_CATCH_TESTCASE( ... ) \
-        INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( dummyFunction ) )
+        INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( dummyFunction ), __VA_ARGS__ )
 
 
 #endif // CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT
@@ -6935,7 +7057,7 @@ namespace Catch {
     struct TestCaseInfo : Detail::NonCopyable {
 
         TestCaseInfo(StringRef _className,
-                     NameAndTags const& _tags,
+                     NameAndTags const& _nameAndTags,
                      SourceLineInfo const& _lineInfo);
 
         bool isHidden() const;
@@ -7148,7 +7270,7 @@ namespace Catch {
 
 #define CATCH_VERSION_MAJOR 3
 #define CATCH_VERSION_MINOR 5
-#define CATCH_VERSION_PATCH 2
+#define CATCH_VERSION_PATCH 4
 
 #endif // CATCH_VERSION_MACROS_HPP_INCLUDED
 
@@ -7820,6 +7942,32 @@ namespace Catch {
 #include <cstdint>
 #include <type_traits>
 
+// Note: We use the usual enable-disable-autodetect dance here even though
+//       we do not support these in CMake configuration options (yet?).
+//       It is highly unlikely that we will need to make these actually
+//       user-configurable, but this will make it simpler if weend up needing
+//       it, and it provides an escape hatch to the users who need it.
+#if defined( __SIZEOF_INT128__ )
+#    define CATCH_CONFIG_INTERNAL_UINT128
+#elif defined( _MSC_VER ) && ( defined( _WIN64 ) || defined( _M_ARM64 ) )
+#    define CATCH_CONFIG_INTERNAL_MSVC_UMUL128
+#endif
+
+#if defined( CATCH_CONFIG_INTERNAL_UINT128 ) && \
+    !defined( CATCH_CONFIG_NO_UINT128 ) &&      \
+    !defined( CATCH_CONFIG_UINT128 )
+#define CATCH_CONFIG_UINT128
+#endif
+
+#if defined( CATCH_CONFIG_INTERNAL_MSVC_UMUL128 ) && \
+    !defined( CATCH_CONFIG_NO_MSVC_UMUL128 ) &&      \
+    !defined( CATCH_CONFIG_MSVC_UMUL128 )
+#    define CATCH_CONFIG_MSVC_UMUL128
+#    include <intrin.h>
+#    pragma intrinsic( _umul128 )
+#endif
+
+
 namespace Catch {
     namespace Detail {
 
@@ -7847,65 +7995,57 @@ namespace Catch {
         struct ExtendedMultResult {
             T upper;
             T lower;
-            friend bool operator==( ExtendedMultResult const& lhs,
-                                    ExtendedMultResult const& rhs ) {
-                return lhs.upper == rhs.upper && lhs.lower == rhs.lower;
+            bool operator==( ExtendedMultResult const& rhs ) const {
+                return upper == rhs.upper && lower == rhs.lower;
             }
         };
 
-        // Returns 128 bit result of multiplying lhs and rhs
+        /**
+         * Returns 128 bit result of lhs * rhs using portable C++ code
+         *
+         * This implementation is almost twice as fast as naive long multiplication,
+         * and unlike intrinsic-based approach, it supports constexpr evaluation.
+         */
         constexpr ExtendedMultResult<std::uint64_t>
-        extendedMult( std::uint64_t lhs, std::uint64_t rhs ) {
-            // We use the simple long multiplication approach for
-            // correctness, we can use platform specific builtins
-            // for performance later.
-
-            // Split the lhs and rhs into two 32bit "digits", so that we can
-            // do 64 bit arithmetic to handle carry bits.
-            //            32b    32b    32b    32b
-            //     lhs                  L1     L2
-            //   * rhs                  R1     R2
-            //            ------------------------
-            //                       |  R2 * L2  |
-            //                 |  R2 * L1  |
-            //                 |  R1 * L2  |
-            //           |  R1 * L1  |
-            //           -------------------------
-            //           |  a  |  b  |  c  |  d  |
-
+        extendedMultPortable(std::uint64_t lhs, std::uint64_t rhs) {
 #define CarryBits( x ) ( x >> 32 )
 #define Digits( x ) ( x & 0xFF'FF'FF'FF )
+            std::uint64_t lhs_low = Digits( lhs );
+            std::uint64_t rhs_low = Digits( rhs );
+            std::uint64_t low_low = ( lhs_low * rhs_low );
+            std::uint64_t high_high = CarryBits( lhs ) * CarryBits( rhs );
 
-            auto r2l2 = Digits( rhs ) * Digits( lhs );
-            auto r2l1 = Digits( rhs ) * CarryBits( lhs );
-            auto r1l2 = CarryBits( rhs ) * Digits( lhs );
-            auto r1l1 = CarryBits( rhs ) * CarryBits( lhs );
-
-            // Sum to columns first
-            auto d = Digits( r2l2 );
-            auto c = CarryBits( r2l2 ) + Digits( r2l1 ) + Digits( r1l2 );
-            auto b = CarryBits( r2l1 ) + CarryBits( r1l2 ) + Digits( r1l1 );
-            auto a = CarryBits( r1l1 );
-
-            // Propagate carries between columns
-            c += CarryBits( d );
-            b += CarryBits( c );
-            a += CarryBits( b );
-
-            // Remove the used carries
-            c = Digits( c );
-            b = Digits( b );
-            a = Digits( a );
+            // We add in carry bits from low-low already
+            std::uint64_t high_low =
+                ( CarryBits( lhs ) * rhs_low ) + CarryBits( low_low );
+            // Note that we can add only low bits from high_low, to avoid
+            // overflow with large inputs
+            std::uint64_t low_high =
+                ( lhs_low * CarryBits( rhs ) ) + Digits( high_low );
 
+            return { high_high + CarryBits( high_low ) + CarryBits( low_high ),
+                     ( low_high << 32 ) | Digits( low_low ) };
 #undef CarryBits
 #undef Digits
-
-            return {
-                a << 32 | b, // upper 64 bits
-                c << 32 | d  // lower 64 bits
-            };
         }
 
+        //! Returns 128 bit result of lhs * rhs
+        inline ExtendedMultResult<std::uint64_t>
+        extendedMult( std::uint64_t lhs, std::uint64_t rhs ) {
+#if defined( CATCH_CONFIG_UINT128 )
+            auto result = __uint128_t( lhs ) * __uint128_t( rhs );
+            return { static_cast<std::uint64_t>( result >> 64 ),
+                     static_cast<std::uint64_t>( result ) };
+#elif defined( CATCH_CONFIG_MSVC_UMUL128 )
+            std::uint64_t high;
+            std::uint64_t low = _umul128( lhs, rhs, &high );
+            return { high, low };
+#else
+            return extendedMultPortable( lhs, rhs );
+#endif
+        }
+
+
         template <typename UInt>
         constexpr ExtendedMultResult<UInt> extendedMult( UInt lhs, UInt rhs ) {
             static_assert( std::is_unsigned<UInt>::value,
@@ -8009,22 +8149,6 @@ namespace Catch {
 
 namespace Catch {
 
-    namespace Detail {
-        // Indirection to enable make_unsigned<bool> behaviour.
-        template <typename T>
-        struct make_unsigned {
-            using type = std::make_unsigned_t<T>;
-        };
-
-        template <>
-        struct make_unsigned<bool> {
-            using type = uint8_t;
-        };
-
-        template <typename T>
-        using make_unsigned_t = typename make_unsigned<T>::type;
-    }
-
 /**
  * Implementation of uniform distribution on integers.
  *
@@ -8040,7 +8164,7 @@ template <typename IntegerType>
 class uniform_integer_distribution {
     static_assert(std::is_integral<IntegerType>::value, "...");
 
-    using UnsignedIntegerType = Detail::make_unsigned_t<IntegerType>;
+    using UnsignedIntegerType = Detail::SizedUnsignedType_t<sizeof(IntegerType)>;
 
     // Only the left bound is stored, and we store it converted to its
     // unsigned image. This avoids having to do the conversions inside
@@ -9322,7 +9446,7 @@ namespace Catch {
 
             std::vector<Catch::Detail::unique_ptr<EnumInfo>> m_enumInfos;
 
-            EnumInfo const& registerEnum( StringRef enumName, StringRef allEnums, std::vector<int> const& values) override;
+            EnumInfo const& registerEnum( StringRef enumName, StringRef allValueNames, std::vector<int> const& values) override;
         };
 
         std::vector<StringRef> parseEnums( StringRef enums );
@@ -9795,7 +9919,7 @@ namespace Catch {
         JsonObjectWriter( std::ostream& os );
         JsonObjectWriter( std::ostream& os, std::uint64_t indent_level );
 
-        JsonObjectWriter( JsonObjectWriter&& source );
+        JsonObjectWriter( JsonObjectWriter&& source ) noexcept;
         JsonObjectWriter& operator=( JsonObjectWriter&& source ) = delete;
 
         ~JsonObjectWriter();
@@ -9814,7 +9938,7 @@ namespace Catch {
         JsonArrayWriter( std::ostream& os );
         JsonArrayWriter( std::ostream& os, std::uint64_t indent_level );
 
-        JsonArrayWriter( JsonArrayWriter&& source );
+        JsonArrayWriter( JsonArrayWriter&& source ) noexcept;
         JsonArrayWriter& operator=( JsonArrayWriter&& source ) = delete;
 
         ~JsonArrayWriter();
@@ -10709,6 +10833,8 @@ namespace Catch {
         std::vector<TestCaseHandle> const& getAllTests() const override;
         std::vector<TestCaseHandle> const& getAllTestsSorted( IConfig const& config ) const override;
 
+        ~TestRegistry() override; // = default
+
     private:
         std::vector<Detail::unique_ptr<TestCaseInfo>> m_owned_test_infos;
         // Keeps a materialized vector for `getAllInfos`.
@@ -13454,7 +13580,7 @@ namespace Catch {
 
         void assertionEnded( AssertionStats const& assertionStats ) override;
         void sectionEnded( SectionStats const& sectionStats ) override;
-        void testCasePartialEnded(TestCaseStats const& testInfo, uint64_t partNumber) override;
+        void testCasePartialEnded(TestCaseStats const& testStats, uint64_t partNumber) override;
         void testCaseEnded( TestCaseStats const& testCaseStats ) override;
         void testRunEnded( TestRunStats const& testRunStats ) override;
 
@@ -13622,7 +13748,7 @@ namespace Catch {
             xml.endElement();
         }
 
-        void writeRun( TestRunNode const& groupNode );
+        void writeRun( TestRunNode const& runNode );
 
         void writeTestFile(StringRef filename, std::vector<TestCaseNode const*> const& testCaseNodes);
 
@@ -13707,8 +13833,8 @@ namespace Catch {
             return "Reports test results as TeamCity service messages"s;
         }
 
-        void testRunStarting( TestRunInfo const& groupInfo ) override;
-        void testRunEnded( TestRunStats const& testGroupStats ) override;
+        void testRunStarting( TestRunInfo const& runInfo ) override;
+        void testRunEnded( TestRunStats const& runStats ) override;
 
 
         void assertionEnded(AssertionStats const& assertionStats) override;

meson.build

@@ -8,7 +8,7 @@
 project(
   'catch2',
   'cpp',
-  version: '3.5.2', # CML version placeholder, don't delete
+  version: '3.5.4', # CML version placeholder, don't delete
   license: 'BSL-1.0',
   meson_version: '>=0.54.1',
 )

src/CMakeLists.txt

@@ -354,7 +354,7 @@ endif()
 add_library(Catch2::Catch2 ALIAS Catch2)
 
 if (ANDROID)
-    target_link_libraries(Catch2 INTERFACE log)
+    target_link_libraries(Catch2 PRIVATE log)
 endif()
 
 set_target_properties(Catch2 PROPERTIES
@@ -362,29 +362,10 @@ set_target_properties(Catch2 PROPERTIES
                                 VERSION ${PROJECT_VERSION}
                               SOVERSION ${PROJECT_VERSION})
 
-# depend on bunch of C++11 and C++14 features to have C++14 enabled by default
+# require C++14
 target_compile_features(Catch2
   PUBLIC
-    cxx_alignas
-    cxx_alignof
-    cxx_attributes
-    cxx_auto_type
-    cxx_constexpr
-    cxx_defaulted_functions
-    cxx_deleted_functions
-    cxx_final
-    cxx_lambdas
-    cxx_noexcept
-    cxx_override
-    cxx_range_for
-    cxx_rvalue_references
-    cxx_static_assert
-    cxx_strong_enums
-    cxx_trailing_return_types
-    cxx_unicode_literals
-    cxx_user_literals
-    cxx_variable_templates
-    cxx_variadic_macros
+    cxx_std_14
 )
 
 configure_file(
@@ -475,26 +456,7 @@ if (CATCH_BUILD_EXAMPLES OR CATCH_BUILD_EXTRA_TESTS)
     )
     target_compile_features(Catch2_buildall_interface
       INTERFACE
-        cxx_alignas
-        cxx_alignof
-        cxx_attributes
-        cxx_auto_type
-        cxx_constexpr
-        cxx_defaulted_functions
-        cxx_deleted_functions
-        cxx_final
-        cxx_lambdas
-        cxx_noexcept
-        cxx_override
-        cxx_range_for
-        cxx_rvalue_references
-        cxx_static_assert
-        cxx_strong_enums
-        cxx_trailing_return_types
-        cxx_unicode_literals
-        cxx_user_literals
-        cxx_variable_templates
-        cxx_variadic_macros
+        cxx_std_14
     )
 endif()
 

src/catch2/benchmark/detail/catch_analyse.cpp

@@ -63,8 +63,8 @@ namespace Catch {
                     FDuration mean = FDuration(0);
                     int i = 0;
                     for (auto it = first; it < last; ++it, ++i) {
-                        samples.push_back(FDuration(*it));
-                        mean += FDuration(*it);
+                        samples.push_back(*it);
+                        mean += *it;
                     }
                     mean /= i;
 

src/catch2/benchmark/detail/catch_stats.cpp

@@ -12,6 +12,7 @@
 #include <catch2/internal/catch_compiler_capabilities.hpp>
 #include <catch2/internal/catch_floating_point_helpers.hpp>
 #include <catch2/internal/catch_random_number_generator.hpp>
+#include <catch2/internal/catch_uniform_integer_distribution.hpp>
 
 #include <algorithm>
 #include <cassert>
@@ -38,7 +39,7 @@ namespace Catch {
                           double const* last,
                           Estimator& estimator ) {
                     auto n = static_cast<size_t>( last - first );
-                    std::uniform_int_distribution<size_t> dist( 0, n - 1 );
+                    Catch::uniform_integer_distribution<size_t> dist( 0, n - 1 );
 
                     sample out;
                     out.reserve( resamples );

src/catch2/catch_approx.cpp

@@ -25,7 +25,7 @@ bool marginComparison(double lhs, double rhs, double margin) {
 namespace Catch {
 
     Approx::Approx ( double value )
-    :   m_epsilon( std::numeric_limits<float>::epsilon()*100. ),
+    :   m_epsilon( static_cast<double>(std::numeric_limits<float>::epsilon())*100. ),
         m_margin( 0.0 ),
         m_scale( 0.0 ),
         m_value( value )

src/catch2/catch_config.cpp

@@ -107,14 +107,16 @@ namespace Catch {
 
         // Insert the default reporter if user hasn't asked for a specific one
         if ( m_data.reporterSpecifications.empty() ) {
-            m_data.reporterSpecifications.push_back( {
 #if defined( CATCH_CONFIG_DEFAULT_REPORTER )
-                CATCH_CONFIG_DEFAULT_REPORTER,
+            const auto default_spec = CATCH_CONFIG_DEFAULT_REPORTER;
 #else
-                "console",
+            const auto default_spec = "console";
 #endif
-                {}, {}, {}
-            } );
+            auto parsed = parseReporterSpec(default_spec);
+            CATCH_ENFORCE( parsed,
+                           "Cannot parse the provided default reporter spec: '"
+                               << default_spec << '\'' );
+            m_data.reporterSpecifications.push_back( std::move( *parsed ) );
         }
 
         if ( enableBazelEnvSupport() ) {

src/catch2/catch_message.cpp

@@ -91,6 +91,7 @@ namespace Catch {
                     m_messages.back().message += " := ";
                     start = pos;
                 }
+            default:; // noop
             }
         }
         assert(openings.empty() && "Mismatched openings");

src/catch2/catch_registry_hub.cpp

@@ -20,7 +20,6 @@
 #include <catch2/internal/catch_noncopyable.hpp>
 #include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
 #include <catch2/internal/catch_move_and_forward.hpp>
-#include <catch2/internal/catch_reporter_registry.hpp>
 
 #include <exception>
 

src/catch2/catch_test_case_info.cpp

@@ -85,8 +85,10 @@ namespace Catch {
             while (lastDot > 0 && filename[lastDot - 1] != '.') {
                 --lastDot;
             }
-            --lastDot;
+            // In theory we could have filename without any extension in it
+            if ( lastDot == 0 ) { return StringRef(); }
 
+            --lastDot;
             size_t nameStart = lastDot;
             while (nameStart > 0 && filename[nameStart - 1] != '/' && filename[nameStart - 1] != '\\') {
                 --nameStart;

src/catch2/catch_test_case_info.hpp

@@ -68,7 +68,7 @@ namespace Catch {
     struct TestCaseInfo : Detail::NonCopyable {
 
         TestCaseInfo(StringRef _className,
-                     NameAndTags const& _tags,
+                     NameAndTags const& _nameAndTags,
                      SourceLineInfo const& _lineInfo);
 
         bool isHidden() const;

src/catch2/catch_tostring.cpp

@@ -54,13 +54,13 @@ namespace Detail {
         }
     } // end unnamed namespace
 
-    std::string convertIntoString(StringRef string, bool escape_invisibles) {
+    std::string convertIntoString(StringRef string, bool escapeInvisibles) {
         std::string ret;
         // This is enough for the "don't escape invisibles" case, and a good
         // lower bound on the "escape invisibles" case.
         ret.reserve(string.size() + 2);
 
-        if (!escape_invisibles) {
+        if (!escapeInvisibles) {
             ret += '"';
             ret += string;
             ret += '"';
@@ -138,7 +138,7 @@ std::string StringMaker<char const*>::convert(char const* str) {
         return{ "{null string}" };
     }
 }
-std::string StringMaker<char*>::convert(char* str) {
+std::string StringMaker<char*>::convert(char* str) { // NOLINT(readability-non-const-parameter)
     if (str) {
         return Detail::convertIntoString( str );
     } else {
@@ -235,8 +235,8 @@ std::string StringMaker<signed char>::convert(signed char value) {
 std::string StringMaker<char>::convert(char c) {
     return ::Catch::Detail::stringify(static_cast<signed char>(c));
 }
-std::string StringMaker<unsigned char>::convert(unsigned char c) {
-    return ::Catch::Detail::stringify(static_cast<char>(c));
+std::string StringMaker<unsigned char>::convert(unsigned char value) {
+    return ::Catch::Detail::stringify(static_cast<char>(value));
 }
 
 int StringMaker<float>::precision = 5;

src/catch2/catch_tostring.hpp

@@ -279,11 +279,11 @@ namespace Catch {
     };
     template<>
     struct StringMaker<signed char> {
-        static std::string convert(signed char c);
+        static std::string convert(signed char value);
     };
     template<>
     struct StringMaker<unsigned char> {
-        static std::string convert(unsigned char c);
+        static std::string convert(unsigned char value);
     };
 
     template<>

src/catch2/catch_version.cpp

@@ -36,7 +36,7 @@ namespace Catch {
     }
 
     Version const& libraryVersion() {
-        static Version version( 3, 5, 2, "", 0 );
+        static Version version( 3, 5, 4, "", 0 );
         return version;
     }
 

src/catch2/catch_version_macros.hpp

@@ -10,6 +10,6 @@
 
 #define CATCH_VERSION_MAJOR 3
 #define CATCH_VERSION_MINOR 5
-#define CATCH_VERSION_PATCH 2
+#define CATCH_VERSION_PATCH 4
 
 #endif // CATCH_VERSION_MACROS_HPP_INCLUDED

src/catch2/internal/catch_commandline.cpp

@@ -47,7 +47,7 @@ namespace Catch {
                     line = trim(line);
                     if( !line.empty() && !startsWith( line, '#' ) ) {
                         if( !startsWith( line, '"' ) )
-                            line = '"' + line + '"';
+                            line = '"' + CATCH_MOVE(line) + '"';
                         config.testsOrTags.push_back( line );
                         config.testsOrTags.emplace_back( "," );
                     }

src/catch2/internal/catch_compiler_capabilities.hpp

@@ -29,14 +29,14 @@
 
 #ifdef __cplusplus
 
-#  if (__cplusplus >= 201402L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 201402L)
-#    define CATCH_CPP14_OR_GREATER
-#  endif
-
 #  if (__cplusplus >= 201703L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
 #    define CATCH_CPP17_OR_GREATER
 #  endif
 
+#  if (__cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
+#    define CATCH_CPP20_OR_GREATER
+#  endif
+
 #endif
 
 // Only GCC compiler should be used in this block, so other compilers trying to

src/catch2/internal/catch_console_colour.cpp

@@ -230,21 +230,21 @@ namespace {
 
 namespace Catch {
 
-    Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode implSelection,
+    Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode colourSelection,
                                                    IStream* stream ) {
 #if defined( CATCH_CONFIG_COLOUR_WIN32 )
-        if ( implSelection == ColourMode::Win32 ) {
+        if ( colourSelection == ColourMode::Win32 ) {
             return Detail::make_unique<Win32ColourImpl>( stream );
         }
 #endif
-        if ( implSelection == ColourMode::ANSI ) {
+        if ( colourSelection == ColourMode::ANSI ) {
             return Detail::make_unique<ANSIColourImpl>( stream );
         }
-        if ( implSelection == ColourMode::None ) {
+        if ( colourSelection == ColourMode::None ) {
             return Detail::make_unique<NoColourImpl>( stream );
         }
 
-        if ( implSelection == ColourMode::PlatformDefault) {
+        if ( colourSelection == ColourMode::PlatformDefault) {
 #if defined( CATCH_CONFIG_COLOUR_WIN32 )
             if ( Win32ColourImpl::useImplementationForStream( *stream ) ) {
                 return Detail::make_unique<Win32ColourImpl>( stream );
@@ -256,7 +256,7 @@ namespace Catch {
             return Detail::make_unique<NoColourImpl>( stream );
         }
 
-        CATCH_ERROR( "Could not create colour impl for selection " << static_cast<int>(implSelection) );
+        CATCH_ERROR( "Could not create colour impl for selection " << static_cast<int>(colourSelection) );
     }
 
     bool isColourImplAvailable( ColourMode colourSelection ) {

src/catch2/internal/catch_decomposer.cpp

@@ -10,7 +10,12 @@
 
 namespace Catch {
 
-    ITransientExpression::~ITransientExpression() = default;
+    void ITransientExpression::streamReconstructedExpression(
+        std::ostream& os ) const {
+        // We can't make this function pure virtual to keep ITransientExpression
+        // constexpr, so we write error message instead
+        os << "Some class derived from ITransientExpression without overriding streamReconstructedExpression";
+    }
 
     void formatReconstructedExpression( std::ostream &os, std::string const& lhs, StringRef op, std::string const& rhs ) {
         if( lhs.size() + rhs.size() < 40 &&

src/catch2/internal/catch_decomposer.hpp

@@ -13,10 +13,91 @@
 #include <catch2/internal/catch_compare_traits.hpp>
 #include <catch2/internal/catch_test_failure_exception.hpp>
 #include <catch2/internal/catch_logical_traits.hpp>
+#include <catch2/internal/catch_compiler_capabilities.hpp>
 
 #include <type_traits>
 #include <iosfwd>
 
+/** \file
+ * Why does decomposing look the way it does:
+ *
+ * Conceptually, decomposing is simple. We change `REQUIRE( a == b )` into
+ * `Decomposer{} <= a == b`, so that `Decomposer{} <= a` is evaluated first,
+ * and our custom operator is used for `a == b`, because `a` is transformed
+ * into `ExprLhs<T&>` and then into `BinaryExpr<T&, U&>`.
+ *
+ * In practice, decomposing ends up a mess, because we have to support
+ * various fun things.
+ *
+ * 1) Types that are only comparable with literal 0, and they do this by
+ *    comparing against a magic type with pointer constructor and deleted
+ *    other constructors. Example: `REQUIRE((a <=> b) == 0)` in libstdc++
+ *
+ * 2) Types that are only comparable with literal 0, and they do this by
+ *    comparing against a magic type with consteval integer constructor.
+ *    Example: `REQUIRE((a <=> b) == 0)` in current MSVC STL.
+ *
+ * 3) Types that have no linkage, and so we cannot form a reference to
+ *    them. Example: some implementations of traits.
+ *
+ * 4) Starting with C++20, when the compiler sees `a == b`, it also uses
+ *    `b == a` when constructing the overload set. For us this means that
+ *    when the compiler handles `ExprLhs<T> == b`, it also tries to resolve
+ *    the overload set for `b == ExprLhs<T>`.
+ *
+ * To accomodate these use cases, decomposer ended up rather complex.
+ *
+ * 1) These types are handled by adding SFINAE overloads to our comparison
+ *    operators, checking whether `T == U` are comparable with the given
+ *    operator, and if not, whether T (or U) are comparable with literal 0.
+ *    If yes, the overload compares T (or U) with 0 literal inline in the
+ *    definition.
+ *
+ *    Note that for extra correctness, we check  that the other type is
+ *    either an `int` (literal 0 is captured as `int` by templates), or
+ *    a `long` (some platforms use 0L for `NULL` and we want to support
+ *    that for pointer comparisons).
+ *
+ * 2) For these types, `is_foo_comparable<T, int>` is true, but letting
+ *    them fall into the overload that actually does `T == int` causes
+ *    compilation error. Handling them requires that the decomposition
+ *    is `constexpr`, so that P2564R3 applies and the `consteval` from
+ *    their accompanying magic type is propagated through the `constexpr`
+ *    call stack.
+ *
+ *    However this is not enough to handle these types automatically,
+ *    because our default is to capture types by reference, to avoid
+ *    runtime copies. While these references cannot become dangling,
+ *    they outlive the constexpr context and thus the default capture
+ *    path cannot be actually constexpr.
+ *
+ *    The solution is to capture these types by value, by explicitly
+ *    specializing `Catch::capture_by_value` for them. Catch2 provides
+ *    specialization for `std::foo_ordering`s, but users can specialize
+ *    the trait for their own types as well.
+ *
+ * 3) If a type has no linkage, we also cannot capture it by reference.
+ *    The solution is once again to capture them by value. We handle
+ *    the common cases by using `std::is_arithmetic` as the default
+ *    for `Catch::capture_by_value`, but that is only a some-effort
+ *    heuristic. But as with 2), users can specialize `capture_by_value`
+ *    for their own types as needed.
+ *
+ * 4) To support C++20 and make the SFINAE on our decomposing operators
+ *    work, the SFINAE has to happen in return type, rather than in
+ *    a template type. This is due to our use of logical type traits
+ *    (`conjunction`/`disjunction`/`negation`), that we use to workaround
+ *    an issue in older (9-) versions of GCC. I still blame C++20 for
+ *    this, because without the comparison order switching, the logical
+ *    traits could still be used in template type.
+ *
+ * There are also other side concerns, e.g. supporting both `REQUIRE(a)`
+ * and `REQUIRE(a == b)`, or making `REQUIRE_THAT(a, IsEqual(b))` slot
+ * nicely into the same expression handling logic, but these are rather
+ * straightforward and add only a bit of complexity (e.g. common base
+ * class for decomposed expressions).
+ */
+
 #ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable:4389) // '==' : signed/unsigned mismatch
@@ -34,8 +115,39 @@
 #  pragma GCC diagnostic ignored "-Wsign-compare"
 #endif
 
+#if defined(CATCH_CPP20_OR_GREATER) && __has_include(<compare>)
+#  include <compare>
+#    if defined( __cpp_lib_three_way_comparison ) && \
+            __cpp_lib_three_way_comparison >= 201907L
+#      define CATCH_CONFIG_CPP20_COMPARE_OVERLOADS
+#    endif
+#endif
+
 namespace Catch {
 
+    namespace Detail {
+        // This was added in C++20, but we require only C++14 for now.
+        template <typename T>
+        using RemoveCVRef_t = std::remove_cv_t<std::remove_reference_t<T>>;
+    }
+
+    // Note: There is nothing that stops us from extending this,
+    //       e.g. to `std::is_scalar`, but the more encompassing
+    //       traits are usually also more expensive. For now we
+    //       keep this as it used to be and it can be changed later.
+    template <typename T>
+    struct capture_by_value
+        : std::integral_constant<bool, std::is_arithmetic<T>{}> {};
+
+#if defined( CATCH_CONFIG_CPP20_COMPARE_OVERLOADS )
+    template <>
+    struct capture_by_value<std::strong_ordering> : std::true_type {};
+    template <>
+    struct capture_by_value<std::weak_ordering> : std::true_type {};
+    template <>
+    struct capture_by_value<std::partial_ordering> : std::true_type {};
+#endif
+
     template <typename T>
     struct always_false : std::false_type {};
 
@@ -44,11 +156,12 @@ namespace Catch {
         bool m_result;
 
     public:
-        auto isBinaryExpression() const -> bool { return m_isBinaryExpression; }
-        auto getResult() const -> bool { return m_result; }
-        virtual void streamReconstructedExpression( std::ostream &os ) const = 0;
+        constexpr auto isBinaryExpression() const -> bool { return m_isBinaryExpression; }
+        constexpr auto getResult() const -> bool { return m_result; }
+        //! This function **has** to be overriden by the derived class.
+        virtual void streamReconstructedExpression( std::ostream& os ) const;
 
-        ITransientExpression( bool isBinaryExpression, bool result )
+        constexpr ITransientExpression( bool isBinaryExpression, bool result )
         :   m_isBinaryExpression( isBinaryExpression ),
             m_result( result )
         {}
@@ -57,14 +170,13 @@ namespace Catch {
         ITransientExpression(ITransientExpression const&) = default;
         ITransientExpression& operator=(ITransientExpression const&) = default;
 
-        // We don't actually need a virtual destructor, but many static analysers
-        // complain if it's not here :-(
-        virtual ~ITransientExpression(); // = default;
-
         friend std::ostream& operator<<(std::ostream& out, ITransientExpression const& expr) {
             expr.streamReconstructedExpression(out);
             return out;
         }
+
+    protected:
+        ~ITransientExpression() = default;
     };
 
     void formatReconstructedExpression( std::ostream &os, std::string const& lhs, StringRef op, std::string const& rhs );
@@ -81,7 +193,7 @@ namespace Catch {
         }
 
     public:
-        BinaryExpr( bool comparisonResult, LhsT lhs, StringRef op, RhsT rhs )
+        constexpr BinaryExpr( bool comparisonResult, LhsT lhs, StringRef op, RhsT rhs )
         :   ITransientExpression{ true, comparisonResult },
             m_lhs( lhs ),
             m_op( op ),
@@ -154,7 +266,7 @@ namespace Catch {
         }
 
     public:
-        explicit UnaryExpr( LhsT lhs )
+        explicit constexpr UnaryExpr( LhsT lhs )
         :   ITransientExpression{ false, static_cast<bool>(lhs) },
             m_lhs( lhs )
         {}
@@ -165,31 +277,31 @@ namespace Catch {
     class ExprLhs {
         LhsT m_lhs;
     public:
-        explicit ExprLhs( LhsT lhs ) : m_lhs( lhs ) {}
+        explicit constexpr ExprLhs( LhsT lhs ) : m_lhs( lhs ) {}
 
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR( id, op )           \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                Detail::negation<std::is_arithmetic<           \
-                                    std::remove_reference_t<RhsT>>>>::value,   \
+                                Detail::negation<capture_by_value<             \
+                                    Detail::RemoveCVRef_t<RhsT>>>>::value,     \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                std::is_arithmetic<RhsT>>::value,              \
+                                capture_by_value<RhsT>>::value,                \
             BinaryExpr<LhsT, RhsT>> {                                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_eq_0_comparable<LhsT>,                              \
@@ -202,8 +314,8 @@ namespace Catch {
             static_cast<bool>( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs };   \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_eq_0_comparable<RhsT>,                              \
@@ -220,29 +332,30 @@ namespace Catch {
 
     #undef CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR
 
+
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( id, op )         \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                Detail::negation<std::is_arithmetic<           \
-                                    std::remove_reference_t<RhsT>>>>::value,   \
+                                Detail::negation<capture_by_value<             \
+                                    Detail::RemoveCVRef_t<RhsT>>>>::value,     \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<Detail::is_##id##_comparable<LhsT, RhsT>,      \
-                                std::is_arithmetic<RhsT>>::value,              \
+                                capture_by_value<RhsT>>::value,                \
             BinaryExpr<LhsT, RhsT>> {                                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_##id##_0_comparable<LhsT>,                          \
@@ -253,8 +366,8 @@ namespace Catch {
             static_cast<bool>( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs };   \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<                                                    \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<                                                   \
             Detail::conjunction<                                               \
                 Detail::negation<Detail::is_##id##_comparable<LhsT, RhsT>>,    \
                 Detail::is_##id##_0_comparable<RhsT>,                          \
@@ -274,17 +387,17 @@ namespace Catch {
 
 #define CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR( op )                        \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )                       \
-        ->std::enable_if_t<                                                    \
-            !std::is_arithmetic<std::remove_reference_t<RhsT>>::value,         \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs )             \
+        -> std::enable_if_t<                                                   \
+            !capture_by_value<Detail::RemoveCVRef_t<RhsT>>::value,             \
             BinaryExpr<LhsT, RhsT const&>> {                                   \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }                                                                          \
     template <typename RhsT>                                                   \
-    friend auto operator op( ExprLhs&& lhs, RhsT rhs )                         \
-        ->std::enable_if_t<std::is_arithmetic<RhsT>::value,                    \
-                           BinaryExpr<LhsT, RhsT>> {                           \
+    constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs )               \
+        -> std::enable_if_t<capture_by_value<RhsT>::value,                     \
+                            BinaryExpr<LhsT, RhsT>> {                          \
         return {                                                               \
             static_cast<bool>( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \
     }
@@ -309,19 +422,22 @@ namespace Catch {
             "wrap the expression inside parentheses, or decompose it");
         }
 
-        auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
+        constexpr auto makeUnaryExpr() const -> UnaryExpr<LhsT> {
             return UnaryExpr<LhsT>{ m_lhs };
         }
     };
 
     struct Decomposer {
-        template<typename T, std::enable_if_t<!std::is_arithmetic<std::remove_reference_t<T>>::value, int> = 0>
-        friend auto operator <= ( Decomposer &&, T && lhs ) -> ExprLhs<T const&> {
+        template <typename T,
+                  std::enable_if_t<!capture_by_value<Detail::RemoveCVRef_t<T>>::value,
+                      int> = 0>
+        constexpr friend auto operator <= ( Decomposer &&, T && lhs ) -> ExprLhs<T const&> {
             return ExprLhs<const T&>{ lhs };
         }
 
-        template<typename T, std::enable_if_t<std::is_arithmetic<T>::value, int> = 0>
-        friend auto operator <= ( Decomposer &&, T value ) -> ExprLhs<T> {
+        template <typename T,
+                  std::enable_if_t<capture_by_value<T>::value, int> = 0>
+        constexpr friend auto operator <= ( Decomposer &&, T value ) -> ExprLhs<T> {
             return ExprLhs<T>{ value };
         }
     };

src/catch2/internal/catch_enum_values_registry.hpp

@@ -24,7 +24,7 @@ namespace Catch {
 
             std::vector<Catch::Detail::unique_ptr<EnumInfo>> m_enumInfos;
 
-            EnumInfo const& registerEnum( StringRef enumName, StringRef allEnums, std::vector<int> const& values) override;
+            EnumInfo const& registerEnum( StringRef enumName, StringRef allValueNames, std::vector<int> const& values) override;
         };
 
         std::vector<StringRef> parseEnums( StringRef enums );

src/catch2/internal/catch_jsonwriter.cpp

@@ -31,7 +31,7 @@ namespace Catch {
         m_os{ os }, m_indent_level{ indent_level } {
         m_os << '{';
     }
-    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ):
+    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ) noexcept:
         m_os{ source.m_os },
         m_indent_level{ source.m_indent_level },
         m_should_comma{ source.m_should_comma },
@@ -62,7 +62,7 @@ namespace Catch {
         m_os{ os }, m_indent_level{ indent_level } {
         m_os << '[';
     }
-    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ):
+    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ) noexcept:
         m_os{ source.m_os },
         m_indent_level{ source.m_indent_level },
         m_should_comma{ source.m_should_comma },

src/catch2/internal/catch_jsonwriter.hpp

@@ -65,7 +65,7 @@ namespace Catch {
         JsonObjectWriter( std::ostream& os );
         JsonObjectWriter( std::ostream& os, std::uint64_t indent_level );
 
-        JsonObjectWriter( JsonObjectWriter&& source );
+        JsonObjectWriter( JsonObjectWriter&& source ) noexcept;
         JsonObjectWriter& operator=( JsonObjectWriter&& source ) = delete;
 
         ~JsonObjectWriter();
@@ -84,7 +84,7 @@ namespace Catch {
         JsonArrayWriter( std::ostream& os );
         JsonArrayWriter( std::ostream& os, std::uint64_t indent_level );
 
-        JsonArrayWriter( JsonArrayWriter&& source );
+        JsonArrayWriter( JsonArrayWriter&& source ) noexcept;
         JsonArrayWriter& operator=( JsonArrayWriter&& source ) = delete;
 
         ~JsonArrayWriter();

src/catch2/internal/catch_platform.hpp

@@ -11,6 +11,9 @@
 // See e.g.:
 // https://opensource.apple.com/source/CarbonHeaders/CarbonHeaders-18.1/TargetConditionals.h.auto.html
 #ifdef __APPLE__
+#  ifndef __has_extension
+#    define __has_extension(x) 0
+#  endif
 #  include <TargetConditionals.h>
 #  if (defined(TARGET_OS_OSX) && TARGET_OS_OSX == 1) || \
       (defined(TARGET_OS_MAC) && TARGET_OS_MAC == 1)

src/catch2/internal/catch_random_integer_helpers.hpp

@@ -14,6 +14,32 @@
 #include <cstdint>
 #include <type_traits>
 
+// Note: We use the usual enable-disable-autodetect dance here even though
+//       we do not support these in CMake configuration options (yet?).
+//       It is highly unlikely that we will need to make these actually
+//       user-configurable, but this will make it simpler if weend up needing
+//       it, and it provides an escape hatch to the users who need it.
+#if defined( __SIZEOF_INT128__ )
+#    define CATCH_CONFIG_INTERNAL_UINT128
+#elif defined( _MSC_VER ) && ( defined( _WIN64 ) || defined( _M_ARM64 ) )
+#    define CATCH_CONFIG_INTERNAL_MSVC_UMUL128
+#endif
+
+#if defined( CATCH_CONFIG_INTERNAL_UINT128 ) && \
+    !defined( CATCH_CONFIG_NO_UINT128 ) &&      \
+    !defined( CATCH_CONFIG_UINT128 )
+#define CATCH_CONFIG_UINT128
+#endif
+
+#if defined( CATCH_CONFIG_INTERNAL_MSVC_UMUL128 ) && \
+    !defined( CATCH_CONFIG_NO_MSVC_UMUL128 ) &&      \
+    !defined( CATCH_CONFIG_MSVC_UMUL128 )
+#    define CATCH_CONFIG_MSVC_UMUL128
+#    include <intrin.h>
+#    pragma intrinsic( _umul128 )
+#endif
+
+
 namespace Catch {
     namespace Detail {
 
@@ -41,65 +67,57 @@ namespace Catch {
         struct ExtendedMultResult {
             T upper;
             T lower;
-            friend bool operator==( ExtendedMultResult const& lhs,
-                                    ExtendedMultResult const& rhs ) {
-                return lhs.upper == rhs.upper && lhs.lower == rhs.lower;
+            bool operator==( ExtendedMultResult const& rhs ) const {
+                return upper == rhs.upper && lower == rhs.lower;
             }
         };
 
-        // Returns 128 bit result of multiplying lhs and rhs
+        /**
+         * Returns 128 bit result of lhs * rhs using portable C++ code
+         *
+         * This implementation is almost twice as fast as naive long multiplication,
+         * and unlike intrinsic-based approach, it supports constexpr evaluation.
+         */
         constexpr ExtendedMultResult<std::uint64_t>
-        extendedMult( std::uint64_t lhs, std::uint64_t rhs ) {
-            // We use the simple long multiplication approach for
-            // correctness, we can use platform specific builtins
-            // for performance later.
-
-            // Split the lhs and rhs into two 32bit "digits", so that we can
-            // do 64 bit arithmetic to handle carry bits.
-            //            32b    32b    32b    32b
-            //     lhs                  L1     L2
-            //   * rhs                  R1     R2
-            //            ------------------------
-            //                       |  R2 * L2  |
-            //                 |  R2 * L1  |
-            //                 |  R1 * L2  |
-            //           |  R1 * L1  |
-            //           -------------------------
-            //           |  a  |  b  |  c  |  d  |
-
+        extendedMultPortable(std::uint64_t lhs, std::uint64_t rhs) {
 #define CarryBits( x ) ( x >> 32 )
 #define Digits( x ) ( x & 0xFF'FF'FF'FF )
+            std::uint64_t lhs_low = Digits( lhs );
+            std::uint64_t rhs_low = Digits( rhs );
+            std::uint64_t low_low = ( lhs_low * rhs_low );
+            std::uint64_t high_high = CarryBits( lhs ) * CarryBits( rhs );
 
-            auto r2l2 = Digits( rhs ) * Digits( lhs );
-            auto r2l1 = Digits( rhs ) * CarryBits( lhs );
-            auto r1l2 = CarryBits( rhs ) * Digits( lhs );
-            auto r1l1 = CarryBits( rhs ) * CarryBits( lhs );
-
-            // Sum to columns first
-            auto d = Digits( r2l2 );
-            auto c = CarryBits( r2l2 ) + Digits( r2l1 ) + Digits( r1l2 );
-            auto b = CarryBits( r2l1 ) + CarryBits( r1l2 ) + Digits( r1l1 );
-            auto a = CarryBits( r1l1 );
-
-            // Propagate carries between columns
-            c += CarryBits( d );
-            b += CarryBits( c );
-            a += CarryBits( b );
-
-            // Remove the used carries
-            c = Digits( c );
-            b = Digits( b );
-            a = Digits( a );
+            // We add in carry bits from low-low already
+            std::uint64_t high_low =
+                ( CarryBits( lhs ) * rhs_low ) + CarryBits( low_low );
+            // Note that we can add only low bits from high_low, to avoid
+            // overflow with large inputs
+            std::uint64_t low_high =
+                ( lhs_low * CarryBits( rhs ) ) + Digits( high_low );
 
+            return { high_high + CarryBits( high_low ) + CarryBits( low_high ),
+                     ( low_high << 32 ) | Digits( low_low ) };
 #undef CarryBits
 #undef Digits
-
-            return {
-                a << 32 | b, // upper 64 bits
-                c << 32 | d  // lower 64 bits
-            };
         }
 
+        //! Returns 128 bit result of lhs * rhs
+        inline ExtendedMultResult<std::uint64_t>
+        extendedMult( std::uint64_t lhs, std::uint64_t rhs ) {
+#if defined( CATCH_CONFIG_UINT128 )
+            auto result = __uint128_t( lhs ) * __uint128_t( rhs );
+            return { static_cast<std::uint64_t>( result >> 64 ),
+                     static_cast<std::uint64_t>( result ) };
+#elif defined( CATCH_CONFIG_MSVC_UMUL128 )
+            std::uint64_t high;
+            std::uint64_t low = _umul128( lhs, rhs, &high );
+            return { high, low };
+#else
+            return extendedMultPortable( lhs, rhs );
+#endif
+        }
+
+
         template <typename UInt>
         constexpr ExtendedMultResult<UInt> extendedMult( UInt lhs, UInt rhs ) {
             static_assert( std::is_unsigned<UInt>::value,

src/catch2/internal/catch_reporter_spec_parser.cpp

@@ -117,7 +117,7 @@ namespace Catch {
             auto kv = splitKVPair( parts[i] );
             auto key = kv.key, value = kv.value;
 
-            if ( key.empty() || value.empty() ) {
+            if ( key.empty() || value.empty() ) { // NOLINT(bugprone-branch-clone)
                 return {};
             } else if ( key[0] == 'X' ) {
                 // This is a reporter-specific option, we don't check these

src/catch2/internal/catch_section.hpp

@@ -69,7 +69,9 @@ namespace Catch {
     namespace Detail {
         // Intentionally without linkage, as it should only be used as a dummy
         // symbol for static analysis.
-        int GetNewSectionHint();
+        // The arguments are used as a dummy for checking warnings in the passed
+        // expressions.
+        int GetNewSectionHint( StringRef, const char* const = nullptr );
     } // namespace Detail
 } // namespace Catch
 
@@ -80,7 +82,8 @@ namespace Catch {
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
         if ( [[maybe_unused]] const int catchInternalPreviousSectionHint =  \
                  catchInternalSectionHint,                                  \
-             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalSectionHint =                                     \
+                 Catch::Detail::GetNewSectionHint(__VA_ARGS__);             \
              catchInternalPreviousSectionHint == __LINE__ )                 \
         CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 
@@ -90,7 +93,8 @@ namespace Catch {
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                             \
         if ( [[maybe_unused]] const int catchInternalPreviousSectionHint =  \
                  catchInternalSectionHint,                                  \
-             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(); \
+             catchInternalSectionHint = Catch::Detail::GetNewSectionHint(   \
+                ( Catch::ReusableStringStream() << __VA_ARGS__ ).str());    \
              catchInternalPreviousSectionHint == __LINE__ )                 \
         CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 

src/catch2/internal/catch_string_manip.cpp

@@ -5,6 +5,7 @@
 //        https://www.boost.org/LICENSE_1_0.txt)
 
 // SPDX-License-Identifier: BSL-1.0
+#include <catch2/internal/catch_move_and_forward.hpp>
 #include <catch2/internal/catch_string_manip.hpp>
 #include <catch2/internal/catch_stringref.hpp>
 
@@ -65,17 +66,29 @@ namespace Catch {
     }
 
     bool replaceInPlace( std::string& str, std::string const& replaceThis, std::string const& withThis ) {
-        bool replaced = false;
         std::size_t i = str.find( replaceThis );
-        while( i != std::string::npos ) {
-            replaced = true;
-            str = str.substr( 0, i ) + withThis + str.substr( i+replaceThis.size() );
-            if( i < str.size()-withThis.size() )
-                i = str.find( replaceThis, i+withThis.size() );
+        if (i == std::string::npos) {
+            return false;
+        }
+        std::size_t copyBegin = 0;
+        std::string origStr = CATCH_MOVE(str);
+        str.clear();
+        // There is at least one replacement, so reserve with the best guess
+        // we can make without actually counting the number of occurences.
+        str.reserve(origStr.size() - replaceThis.size() + withThis.size());
+        do {
+            str.append(origStr, copyBegin, i-copyBegin );
+            str += withThis;
+            copyBegin = i + replaceThis.size();
+            if( copyBegin < origStr.size() )
+                i = origStr.find( replaceThis, copyBegin );
             else
                 i = std::string::npos;
+        } while( i != std::string::npos );
+        if ( copyBegin < origStr.size() ) {
+            str.append(origStr, copyBegin, origStr.size() );
         }
-        return replaced;
+        return true;
     }
 
     std::vector<StringRef> splitStringRef( StringRef str, char delimiter ) {

src/catch2/internal/catch_stringref.hpp

@@ -97,8 +97,8 @@ namespace Catch {
         constexpr const_iterator end() const { return m_start + m_size; }
 
 
-        friend std::string& operator += (std::string& lhs, StringRef sr);
-        friend std::ostream& operator << (std::ostream& os, StringRef sr);
+        friend std::string& operator += (std::string& lhs, StringRef rhs);
+        friend std::ostream& operator << (std::ostream& os, StringRef str);
         friend std::string operator+(StringRef lhs, StringRef rhs);
 
         /**

src/catch2/internal/catch_test_case_registry_impl.cpp

@@ -123,6 +123,8 @@ namespace Catch {
         return getRegistryHub().getTestCaseRegistry().getAllTestsSorted( config );
     }
 
+    TestRegistry::~TestRegistry() = default;
+
     void TestRegistry::registerTest(Detail::unique_ptr<TestCaseInfo> testInfo, Detail::unique_ptr<ITestInvoker> testInvoker) {
         m_handles.emplace_back(testInfo.get(), testInvoker.get());
         m_viewed_test_infos.push_back(testInfo.get());

src/catch2/internal/catch_test_case_registry_impl.hpp

@@ -36,6 +36,8 @@ namespace Catch {
         std::vector<TestCaseHandle> const& getAllTests() const override;
         std::vector<TestCaseHandle> const& getAllTestsSorted( IConfig const& config ) const override;
 
+        ~TestRegistry() override; // = default
+
     private:
         std::vector<Detail::unique_ptr<TestCaseInfo>> m_owned_test_infos;
         // Keeps a materialized vector for `getAllInfos`.

src/catch2/internal/catch_test_macro_impl.hpp

@@ -49,7 +49,7 @@
         INTERNAL_CATCH_TRY { \
             CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
             CATCH_INTERNAL_SUPPRESS_PARENTHESES_WARNINGS \
-            catchAssertionHandler.handleExpr( Catch::Decomposer() <= __VA_ARGS__ ); \
+            catchAssertionHandler.handleExpr( Catch::Decomposer() <= __VA_ARGS__ ); /* NOLINT(bugprone-chained-comparison) */ \
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION \
         } INTERNAL_CATCH_CATCH( catchAssertionHandler ) \
         INTERNAL_CATCH_REACT( catchAssertionHandler ) \

src/catch2/internal/catch_test_registry.hpp

@@ -95,7 +95,7 @@ struct AutoReg : Detail::NonCopyable {
 namespace Catch {
     namespace Detail {
         struct DummyUse {
-            DummyUse( void ( * )( int ) );
+            DummyUse( void ( * )( int ), Catch::NameAndTags const& );
         };
     } // namespace Detail
 } // namespace Catch
@@ -107,18 +107,18 @@ namespace Catch {
 // tests can compile. The redefined `TEST_CASE` shadows this with param.
 static int catchInternalSectionHint = 0;
 
-#    define INTERNAL_CATCH_TESTCASE2( fname )                              \
+#    define INTERNAL_CATCH_TESTCASE2( fname, ... )                         \
         static void fname( int );                                          \
         CATCH_INTERNAL_START_WARNINGS_SUPPRESSION                          \
         CATCH_INTERNAL_SUPPRESS_GLOBALS_WARNINGS                           \
         CATCH_INTERNAL_SUPPRESS_UNUSED_VARIABLE_WARNINGS                   \
         static const Catch::Detail::DummyUse INTERNAL_CATCH_UNIQUE_NAME(   \
-            dummyUser )( &(fname) );                                       \
+            dummyUser )( &(fname), Catch::NameAndTags{ __VA_ARGS__ } );    \
         CATCH_INTERNAL_SUPPRESS_SHADOW_WARNINGS                            \
         static void fname( [[maybe_unused]] int catchInternalSectionHint ) \
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION
 #    define INTERNAL_CATCH_TESTCASE( ... ) \
-        INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( dummyFunction ) )
+        INTERNAL_CATCH_TESTCASE2( INTERNAL_CATCH_UNIQUE_NAME( dummyFunction ), __VA_ARGS__ )
 
 
 #endif // CATCH_CONFIG_EXPERIMENTAL_STATIC_ANALYSIS_SUPPORT

src/catch2/internal/catch_uniform_integer_distribution.hpp

@@ -13,22 +13,6 @@
 
 namespace Catch {
 
-    namespace Detail {
-        // Indirection to enable make_unsigned<bool> behaviour.
-        template <typename T>
-        struct make_unsigned {
-            using type = std::make_unsigned_t<T>;
-        };
-
-        template <>
-        struct make_unsigned<bool> {
-            using type = uint8_t;
-        };
-
-        template <typename T>
-        using make_unsigned_t = typename make_unsigned<T>::type;
-    }
-
 /**
  * Implementation of uniform distribution on integers.
  *
@@ -44,7 +28,7 @@ template <typename IntegerType>
 class uniform_integer_distribution {
     static_assert(std::is_integral<IntegerType>::value, "...");
 
-    using UnsignedIntegerType = Detail::make_unsigned_t<IntegerType>;
+    using UnsignedIntegerType = Detail::SizedUnsignedType_t<sizeof(IntegerType)>;
 
     // Only the left bound is stored, and we store it converted to its
     // unsigned image. This avoids having to do the conversions inside

src/catch2/reporters/catch_reporter_console.cpp

@@ -520,8 +520,8 @@ void ConsoleReporter::testRunEnded(TestRunStats const& _testRunStats) {
     m_stream << '\n' << std::flush;
     StreamingReporterBase::testRunEnded(_testRunStats);
 }
-void ConsoleReporter::testRunStarting(TestRunInfo const& _testInfo) {
-    StreamingReporterBase::testRunStarting(_testInfo);
+void ConsoleReporter::testRunStarting(TestRunInfo const& _testRunInfo) {
+    StreamingReporterBase::testRunStarting(_testRunInfo);
     if ( m_config->testSpec().hasFilters() ) {
         m_stream << m_colour->guardColour( Colour::BrightYellow ) << "Filters: "
                  << m_config->testSpec() << '\n';

src/catch2/reporters/catch_reporter_cumulative_base.cpp

@@ -16,8 +16,7 @@ namespace Catch {
     namespace {
         struct BySectionInfo {
             BySectionInfo( SectionInfo const& other ): m_other( other ) {}
-            BySectionInfo( BySectionInfo const& other ):
-                m_other( other.m_other ) {}
+            BySectionInfo( BySectionInfo const& other ) = default;
             bool operator()(
                 Detail::unique_ptr<CumulativeReporterBase::SectionNode> const&
                     node ) const {

src/catch2/reporters/catch_reporter_json.cpp

@@ -133,8 +133,8 @@ namespace Catch {
         return "Outputs listings as JSON. Test listing is Work-in-Progress!";
     }
 
-    void JsonReporter::testRunStarting( TestRunInfo const& testInfo ) {
-        StreamingReporterBase::testRunStarting( testInfo );
+    void JsonReporter::testRunStarting( TestRunInfo const& runInfo ) {
+        StreamingReporterBase::testRunStarting( runInfo );
         endListing();
 
         assert( isInside( Writer::Object ) );

src/catch2/reporters/catch_reporter_junit.cpp

@@ -74,7 +74,7 @@ namespace Catch {
 
         static void normalizeNamespaceMarkers(std::string& str) {
             std::size_t pos = str.find( "::" );
-            while ( pos != str.npos ) {
+            while ( pos != std::string::npos ) {
                 str.replace( pos, 2, "." );
                 pos += 1;
                 pos = str.find( "::", pos );

src/catch2/reporters/catch_reporter_multi.hpp

@@ -53,7 +53,7 @@ namespace Catch {
 
         void assertionEnded( AssertionStats const& assertionStats ) override;
         void sectionEnded( SectionStats const& sectionStats ) override;
-        void testCasePartialEnded(TestCaseStats const& testInfo, uint64_t partNumber) override;
+        void testCasePartialEnded(TestCaseStats const& testStats, uint64_t partNumber) override;
         void testCaseEnded( TestCaseStats const& testCaseStats ) override;
         void testRunEnded( TestRunStats const& testRunStats ) override;
 

src/catch2/reporters/catch_reporter_sonarqube.hpp

@@ -37,7 +37,7 @@ namespace Catch {
             xml.endElement();
         }
 
-        void writeRun( TestRunNode const& groupNode );
+        void writeRun( TestRunNode const& runNode );
 
         void writeTestFile(StringRef filename, std::vector<TestCaseNode const*> const& testCaseNodes);
 

src/catch2/reporters/catch_reporter_teamcity.hpp

@@ -35,8 +35,8 @@ namespace Catch {
             return "Reports test results as TeamCity service messages"s;
         }
 
-        void testRunStarting( TestRunInfo const& groupInfo ) override;
-        void testRunEnded( TestRunStats const& testGroupStats ) override;
+        void testRunStarting( TestRunInfo const& runInfo ) override;
+        void testRunEnded( TestRunStats const& runStats ) override;
 
 
         void assertionEnded(AssertionStats const& assertionStats) override;

tests/CMakeLists.txt

@@ -59,7 +59,7 @@ if (CATCH_BUILD_SURROGATES)
   )
   target_link_libraries(Catch2SurrogateTarget PRIVATE Catch2WithMain)
 
-endif(CATCH_BUILD_SURROGATES)
+endif()
 
 ####
 # Temporary workaround for VS toolset changes in 2017
@@ -70,7 +70,7 @@ if (MSVC)
 configure_file(${CATCH_DIR}/tools/misc/SelfTest.vcxproj.user
                ${CMAKE_BINARY_DIR}/tests
                COPYONLY)
-endif(MSVC) #Temporary workaround
+endif() #Temporary workaround
 
 
 # define the sources of the self test

tests/ExtraTests/CMakeLists.txt

@@ -183,7 +183,7 @@ if (NOT WIN32)
     PROPERTIES
       PASS_REGULAR_EXPRESSION "Catch will terminate"
   )
-endif(NOT WIN32)
+endif()
 
 
 add_test(NAME CATCH_CONFIG_DISABLE_EXCEPTIONS-3 COMMAND DisabledExceptions-CustomHandler "Tests that run")
@@ -556,6 +556,7 @@ add_executable(AmalgamatedTestCompilation
   ${CATCH_DIR}/extras/catch_amalgamated.cpp
 )
 target_include_directories(AmalgamatedTestCompilation PRIVATE ${CATCH_DIR}/extras)
+target_compile_features(AmalgamatedTestCompilation PRIVATE cxx_std_14)
 
 add_test(NAME AmalgamatedFileTest COMMAND AmalgamatedTestCompilation)
 set_tests_properties(

tests/ExtraTests/X22-BenchmarksInCumulativeReporter.cpp

@@ -34,7 +34,7 @@ public:
         return "Custom reporter for testing cumulative reporter base";
     }
 
-    virtual void testRunEndedCumulative() override;
+    void testRunEndedCumulative() override;
 };
 
 CATCH_REGISTER_REPORTER("testReporter", CumulativeBenchmarkReporter)

tests/ExtraTests/X29-CustomArgumentsForReporters.cpp

@@ -36,6 +36,7 @@ public:
 
     void testRunStarting( Catch::TestRunInfo const& ) override {
         std::vector<std::pair<std::string, std::string>> options;
+        options.reserve( m_customOptions.size() );
         for ( auto const& kv : m_customOptions ) {
             options.push_back( kv );
         }

tests/ExtraTests/X91-AmalgamatedCatch.cpp

@@ -16,10 +16,10 @@
 TEST_CASE("Just a dummy test") {
     auto i = GENERATE(1, 2, 3);
     SECTION("a") {
-        REQUIRE(1 != 4);
+        REQUIRE(i != 4);
     }
     SECTION("b") {
-        CHECK(1 != 5);
+        CHECK(i != 5);
     }
     REQUIRE_THAT(1,
                  Catch::Matchers::Predicate<int>([](int i) {

tests/SelfTest/Baselines/compact.sw.approved.txt

@@ -350,20 +350,16 @@ Details.tests.cpp:<line number>: passed: lt( "a", "b" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "a", "B" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "A", "b" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "A", "B" ) for: true
-ToStringGeneral.tests.cpp:<line number>: passed: tab == '\t' for: '\t' == '\t'
-ToStringGeneral.tests.cpp:<line number>: passed: newline == '\n' for: '\n' == '\n'
-ToStringGeneral.tests.cpp:<line number>: passed: carr_return == '\r' for: '\r' == '\r'
-ToStringGeneral.tests.cpp:<line number>: passed: form_feed == '\f' for: '\f' == '\f'
-ToStringGeneral.tests.cpp:<line number>: passed: space == ' ' for: ' ' == ' '
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'a' == 'a'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'z' == 'z'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'A' == 'A'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'Z' == 'Z'
-ToStringGeneral.tests.cpp:<line number>: passed: null_terminator == '\0' for: 0 == 0
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 2 == 2
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 3 == 3
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 4 == 4
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 5 == 5
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\t') == "'\\t'" for: "'\t'" == "'\t'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\n') == "'\\n'" for: "'\n'" == "'\n'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\r') == "'\\r'" for: "'\r'" == "'\r'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\f') == "'\\f'" for: "'\f'" == "'\f'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( ' ' ) == "' '" for: "' '" == "' '"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( 'A' ) == "'A'" for: "'A'" == "'A'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( 'z' ) == "'z'" for: "'z'" == "'z'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( '\0' ) == "0" for: "0" == "0"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" for: "2" == "2"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" for: "5" == "5"
 Clara.tests.cpp:<line number>: passed: name.empty() for: true
 Clara.tests.cpp:<line number>: passed: name == "foo" for: "foo" == "foo"
 Clara.tests.cpp:<line number>: passed: !(parse_result) for: !{?}
@@ -1737,13 +1733,13 @@ Tag.tests.cpp:<line number>: passed: testCase.tags, VectorContains( Tag( "tag wi
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1.0 == 1
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
+Misc.tests.cpp:<line number>: passed: std::is_default_constructible<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_default_constructible<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_trivially_copyable<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_trivially_copyable<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
 Misc.tests.cpp:<line number>: passed: v.size() == 5 for: 5 == 5
 Misc.tests.cpp:<line number>: passed: v.capacity() >= 5 for: 5 >= 5
 Misc.tests.cpp:<line number>: passed: v.size() == 10 for: 10 == 10
@@ -2483,6 +2479,10 @@ StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(letters, lett
 StringManip.tests.cpp:<line number>: passed: letters == "replaced" for: "replaced" == "replaced"
 StringManip.tests.cpp:<line number>: passed: !(Catch::replaceInPlace(letters, "x", "z")) for: !false
 StringManip.tests.cpp:<line number>: passed: letters == letters for: "abcdefcg" == "abcdefcg"
+StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(letters, "c", "cc") for: true
+StringManip.tests.cpp:<line number>: passed: letters == "abccdefccg" for: "abccdefccg" == "abccdefccg"
+StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(s, "--", "-") for: true
+StringManip.tests.cpp:<line number>: passed: s == "--" for: "--" == "--"
 StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(s, "'", "|'") for: true
 StringManip.tests.cpp:<line number>: passed: s == "didn|'t" for: "didn|'t" == "didn|'t"
 Stream.tests.cpp:<line number>: passed: Catch::makeStream( "%somestream" )

tests/SelfTest/Baselines/compact.sw.multi.approved.txt

@@ -348,20 +348,16 @@ Details.tests.cpp:<line number>: passed: lt( "a", "b" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "a", "B" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "A", "b" ) for: true
 Details.tests.cpp:<line number>: passed: lt( "A", "B" ) for: true
-ToStringGeneral.tests.cpp:<line number>: passed: tab == '\t' for: '\t' == '\t'
-ToStringGeneral.tests.cpp:<line number>: passed: newline == '\n' for: '\n' == '\n'
-ToStringGeneral.tests.cpp:<line number>: passed: carr_return == '\r' for: '\r' == '\r'
-ToStringGeneral.tests.cpp:<line number>: passed: form_feed == '\f' for: '\f' == '\f'
-ToStringGeneral.tests.cpp:<line number>: passed: space == ' ' for: ' ' == ' '
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'a' == 'a'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'z' == 'z'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'A' == 'A'
-ToStringGeneral.tests.cpp:<line number>: passed: c == chars[i] for: 'Z' == 'Z'
-ToStringGeneral.tests.cpp:<line number>: passed: null_terminator == '\0' for: 0 == 0
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 2 == 2
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 3 == 3
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 4 == 4
-ToStringGeneral.tests.cpp:<line number>: passed: c == i for: 5 == 5
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\t') == "'\\t'" for: "'\t'" == "'\t'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\n') == "'\\n'" for: "'\n'" == "'\n'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\r') == "'\\r'" for: "'\r'" == "'\r'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify('\f') == "'\\f'" for: "'\f'" == "'\f'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( ' ' ) == "' '" for: "' '" == "' '"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( 'A' ) == "'A'" for: "'A'" == "'A'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( 'z' ) == "'z'" for: "'z'" == "'z'"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( '\0' ) == "0" for: "0" == "0"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" for: "2" == "2"
+ToStringGeneral.tests.cpp:<line number>: passed: ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" for: "5" == "5"
 Clara.tests.cpp:<line number>: passed: name.empty() for: true
 Clara.tests.cpp:<line number>: passed: name == "foo" for: "foo" == "foo"
 Clara.tests.cpp:<line number>: passed: !(parse_result) for: !{?}
@@ -1730,13 +1726,13 @@ Tag.tests.cpp:<line number>: passed: testCase.tags, VectorContains( Tag( "tag wi
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 Class.tests.cpp:<line number>: passed: Template_Fixture<TestType>::m_a == 1 for: 1.0 == 1
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 1 > 0
-Misc.tests.cpp:<line number>: passed: sizeof(TestType) > 0 for: 4 > 0
+Misc.tests.cpp:<line number>: passed: std::is_default_constructible<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_default_constructible<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_trivially_copyable<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_trivially_copyable<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
+Misc.tests.cpp:<line number>: passed: std::is_arithmetic<TestType>::value for: true
 Misc.tests.cpp:<line number>: passed: v.size() == 5 for: 5 == 5
 Misc.tests.cpp:<line number>: passed: v.capacity() >= 5 for: 5 >= 5
 Misc.tests.cpp:<line number>: passed: v.size() == 10 for: 10 == 10
@@ -2472,6 +2468,10 @@ StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(letters, lett
 StringManip.tests.cpp:<line number>: passed: letters == "replaced" for: "replaced" == "replaced"
 StringManip.tests.cpp:<line number>: passed: !(Catch::replaceInPlace(letters, "x", "z")) for: !false
 StringManip.tests.cpp:<line number>: passed: letters == letters for: "abcdefcg" == "abcdefcg"
+StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(letters, "c", "cc") for: true
+StringManip.tests.cpp:<line number>: passed: letters == "abccdefccg" for: "abccdefccg" == "abccdefccg"
+StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(s, "--", "-") for: true
+StringManip.tests.cpp:<line number>: passed: s == "--" for: "--" == "--"
 StringManip.tests.cpp:<line number>: passed: Catch::replaceInPlace(s, "'", "|'") for: true
 StringManip.tests.cpp:<line number>: passed: s == "didn|'t" for: "didn|'t" == "didn|'t"
 Stream.tests.cpp:<line number>: passed: Catch::makeStream( "%somestream" )

tests/SelfTest/Baselines/console.sw.approved.txt

@@ -2904,24 +2904,24 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( tab == '\t' )
+  CHECK( ::Catch::Detail::stringify('\t') == "'\\t'" )
 with expansion:
-  '\t' == '\t'
+  "'\t'" == "'\t'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( newline == '\n' )
+  CHECK( ::Catch::Detail::stringify('\n') == "'\\n'" )
 with expansion:
-  '\n' == '\n'
+  "'\n'" == "'\n'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( carr_return == '\r' )
+  CHECK( ::Catch::Detail::stringify('\r') == "'\\r'" )
 with expansion:
-  '\r' == '\r'
+  "'\r'" == "'\r'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( form_feed == '\f' )
+  CHECK( ::Catch::Detail::stringify('\f') == "'\\f'" )
 with expansion:
-  '\f' == '\f'
+  "'\f'" == "'\f'"
 
 -------------------------------------------------------------------------------
 Character pretty printing
@@ -2931,29 +2931,19 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( space == ' ' )
+  CHECK( ::Catch::Detail::stringify( ' ' ) == "' '" )
 with expansion:
-  ' ' == ' '
+  "' '" == "' '"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
+  CHECK( ::Catch::Detail::stringify( 'A' ) == "'A'" )
 with expansion:
-  'a' == 'a'
+  "'A'" == "'A'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
+  CHECK( ::Catch::Detail::stringify( 'z' ) == "'z'" )
 with expansion:
-  'z' == 'z'
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
-with expansion:
-  'A' == 'A'
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
-with expansion:
-  'Z' == 'Z'
+  "'z'" == "'z'"
 
 -------------------------------------------------------------------------------
 Character pretty printing
@@ -2963,29 +2953,19 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( null_terminator == '\0' )
+  CHECK( ::Catch::Detail::stringify( '\0' ) == "0" )
 with expansion:
-  0 == 0
+  "0" == "0"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
+  CHECK( ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" )
 with expansion:
-  2 == 2
+  "2" == "2"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
+  CHECK( ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" )
 with expansion:
-  3 == 3
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
-with expansion:
-  4 == 4
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
-with expansion:
-  5 == 5
+  "5" == "5"
 
 -------------------------------------------------------------------------------
 Clara::Arg supports single-arg parse the way Opt does
@@ -11675,9 +11655,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_default_constructible<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-copyable and non-
@@ -11687,9 +11667,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_default_constructible<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-default-constructible
@@ -11699,9 +11679,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_trivially_copyable<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-default-constructible
@@ -11711,9 +11691,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_trivially_copyable<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 0
@@ -11722,9 +11702,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 1
@@ -11733,9 +11713,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 2
@@ -11744,9 +11724,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 TemplateTest: vectors can be sized and resized - float
@@ -17309,6 +17289,42 @@ StringManip.tests.cpp:<line number>: PASSED:
 with expansion:
   "abcdefcg" == "abcdefcg"
 
+-------------------------------------------------------------------------------
+replaceInPlace
+  no replace in already-replaced string
+  lengthening
+-------------------------------------------------------------------------------
+StringManip.tests.cpp:<line number>
+...............................................................................
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( Catch::replaceInPlace(letters, "c", "cc") )
+with expansion:
+  true
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( letters == "abccdefccg" )
+with expansion:
+  "abccdefccg" == "abccdefccg"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  no replace in already-replaced string
+  shortening
+-------------------------------------------------------------------------------
+StringManip.tests.cpp:<line number>
+...............................................................................
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( Catch::replaceInPlace(s, "--", "-") )
+with expansion:
+  true
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( s == "--" )
+with expansion:
+  "--" == "--"
+
 -------------------------------------------------------------------------------
 replaceInPlace
   escape '

tests/SelfTest/Baselines/console.sw.multi.approved.txt

@@ -2902,24 +2902,24 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( tab == '\t' )
+  CHECK( ::Catch::Detail::stringify('\t') == "'\\t'" )
 with expansion:
-  '\t' == '\t'
+  "'\t'" == "'\t'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( newline == '\n' )
+  CHECK( ::Catch::Detail::stringify('\n') == "'\\n'" )
 with expansion:
-  '\n' == '\n'
+  "'\n'" == "'\n'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( carr_return == '\r' )
+  CHECK( ::Catch::Detail::stringify('\r') == "'\\r'" )
 with expansion:
-  '\r' == '\r'
+  "'\r'" == "'\r'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( form_feed == '\f' )
+  CHECK( ::Catch::Detail::stringify('\f') == "'\\f'" )
 with expansion:
-  '\f' == '\f'
+  "'\f'" == "'\f'"
 
 -------------------------------------------------------------------------------
 Character pretty printing
@@ -2929,29 +2929,19 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( space == ' ' )
+  CHECK( ::Catch::Detail::stringify( ' ' ) == "' '" )
 with expansion:
-  ' ' == ' '
+  "' '" == "' '"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
+  CHECK( ::Catch::Detail::stringify( 'A' ) == "'A'" )
 with expansion:
-  'a' == 'a'
+  "'A'" == "'A'"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
+  CHECK( ::Catch::Detail::stringify( 'z' ) == "'z'" )
 with expansion:
-  'z' == 'z'
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
-with expansion:
-  'A' == 'A'
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == chars[i] )
-with expansion:
-  'Z' == 'Z'
+  "'z'" == "'z'"
 
 -------------------------------------------------------------------------------
 Character pretty printing
@@ -2961,29 +2951,19 @@ ToStringGeneral.tests.cpp:<line number>
 ...............................................................................
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  CHECK( null_terminator == '\0' )
+  CHECK( ::Catch::Detail::stringify( '\0' ) == "0" )
 with expansion:
-  0 == 0
+  "0" == "0"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
+  CHECK( ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" )
 with expansion:
-  2 == 2
+  "2" == "2"
 
 ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
+  CHECK( ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" )
 with expansion:
-  3 == 3
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
-with expansion:
-  4 == 4
-
-ToStringGeneral.tests.cpp:<line number>: PASSED:
-  REQUIRE( c == i )
-with expansion:
-  5 == 5
+  "5" == "5"
 
 -------------------------------------------------------------------------------
 Clara::Arg supports single-arg parse the way Opt does
@@ -11668,9 +11648,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_default_constructible<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-copyable and non-
@@ -11680,9 +11660,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_default_constructible<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-default-constructible
@@ -11692,9 +11672,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_trivially_copyable<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside non-default-constructible
@@ -11704,9 +11684,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_trivially_copyable<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 0
@@ -11715,9 +11695,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 1
@@ -11726,9 +11706,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  1 > 0
+  true
 
 -------------------------------------------------------------------------------
 Template test case with test types specified inside std::tuple - MyTypes - 2
@@ -11737,9 +11717,9 @@ Misc.tests.cpp:<line number>
 ...............................................................................
 
 Misc.tests.cpp:<line number>: PASSED:
-  REQUIRE( sizeof(TestType) > 0 )
+  REQUIRE( std::is_arithmetic<TestType>::value )
 with expansion:
-  4 > 0
+  true
 
 -------------------------------------------------------------------------------
 TemplateTest: vectors can be sized and resized - float
@@ -17298,6 +17278,42 @@ StringManip.tests.cpp:<line number>: PASSED:
 with expansion:
   "abcdefcg" == "abcdefcg"
 
+-------------------------------------------------------------------------------
+replaceInPlace
+  no replace in already-replaced string
+  lengthening
+-------------------------------------------------------------------------------
+StringManip.tests.cpp:<line number>
+...............................................................................
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( Catch::replaceInPlace(letters, "c", "cc") )
+with expansion:
+  true
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( letters == "abccdefccg" )
+with expansion:
+  "abccdefccg" == "abccdefccg"
+
+-------------------------------------------------------------------------------
+replaceInPlace
+  no replace in already-replaced string
+  shortening
+-------------------------------------------------------------------------------
+StringManip.tests.cpp:<line number>
+...............................................................................
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( Catch::replaceInPlace(s, "--", "-") )
+with expansion:
+  true
+
+StringManip.tests.cpp:<line number>: PASSED:
+  CHECK( s == "--" )
+with expansion:
+  "--" == "--"
+
 -------------------------------------------------------------------------------
 replaceInPlace
   escape '

tests/SelfTest/Baselines/junit.sw.approved.txt

@@ -1966,6 +1966,8 @@ at Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace last char" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace all chars" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace no chars" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="replaceInPlace/no replace in already-replaced string/lengthening" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="replaceInPlace/no replace in already-replaced string/shortening" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/escape '" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="request an unknown %-starting stream fails" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="resolution" time="{duration}" status="run"/>

tests/SelfTest/Baselines/junit.sw.multi.approved.txt

@@ -1965,6 +1965,8 @@ at Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace last char" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace all chars" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/replace no chars" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="replaceInPlace/no replace in already-replaced string/lengthening" time="{duration}" status="run"/>
+    <testcase classname="<exe-name>.global" name="replaceInPlace/no replace in already-replaced string/shortening" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="replaceInPlace/escape '" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="request an unknown %-starting stream fails" time="{duration}" status="run"/>
     <testcase classname="<exe-name>.global" name="resolution" time="{duration}" status="run"/>

tests/SelfTest/Baselines/sonarqube.sw.approved.txt

@@ -262,6 +262,8 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="replaceInPlace/replace last char" duration="{duration}"/>
     <testCase name="replaceInPlace/replace all chars" duration="{duration}"/>
     <testCase name="replaceInPlace/replace no chars" duration="{duration}"/>
+    <testCase name="replaceInPlace/no replace in already-replaced string/lengthening" duration="{duration}"/>
+    <testCase name="replaceInPlace/no replace in already-replaced string/shortening" duration="{duration}"/>
     <testCase name="replaceInPlace/escape '" duration="{duration}"/>
     <testCase name="splitString" duration="{duration}"/>
     <testCase name="startsWith" duration="{duration}"/>

tests/SelfTest/Baselines/sonarqube.sw.multi.approved.txt

@@ -261,6 +261,8 @@ at AssertionHandler.tests.cpp:<line number>
     <testCase name="replaceInPlace/replace last char" duration="{duration}"/>
     <testCase name="replaceInPlace/replace all chars" duration="{duration}"/>
     <testCase name="replaceInPlace/replace no chars" duration="{duration}"/>
+    <testCase name="replaceInPlace/no replace in already-replaced string/lengthening" duration="{duration}"/>
+    <testCase name="replaceInPlace/no replace in already-replaced string/shortening" duration="{duration}"/>
     <testCase name="replaceInPlace/escape '" duration="{duration}"/>
     <testCase name="splitString" duration="{duration}"/>
     <testCase name="startsWith" duration="{duration}"/>

tests/SelfTest/Baselines/tap.sw.approved.txt

@@ -697,33 +697,25 @@ ok {test-number} - lt( "A", "b" ) for: true
 # CaseInsensitiveLess is case insensitive
 ok {test-number} - lt( "A", "B" ) for: true
 # Character pretty printing
-ok {test-number} - tab == '\t' for: '\t' == '\t'
+ok {test-number} - ::Catch::Detail::stringify('\t') == "'\\t'" for: "'\t'" == "'\t'"
 # Character pretty printing
-ok {test-number} - newline == '\n' for: '\n' == '\n'
+ok {test-number} - ::Catch::Detail::stringify('\n') == "'\\n'" for: "'\n'" == "'\n'"
 # Character pretty printing
-ok {test-number} - carr_return == '\r' for: '\r' == '\r'
+ok {test-number} - ::Catch::Detail::stringify('\r') == "'\\r'" for: "'\r'" == "'\r'"
 # Character pretty printing
-ok {test-number} - form_feed == '\f' for: '\f' == '\f'
+ok {test-number} - ::Catch::Detail::stringify('\f') == "'\\f'" for: "'\f'" == "'\f'"
 # Character pretty printing
-ok {test-number} - space == ' ' for: ' ' == ' '
+ok {test-number} - ::Catch::Detail::stringify( ' ' ) == "' '" for: "' '" == "' '"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'a' == 'a'
+ok {test-number} - ::Catch::Detail::stringify( 'A' ) == "'A'" for: "'A'" == "'A'"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'z' == 'z'
+ok {test-number} - ::Catch::Detail::stringify( 'z' ) == "'z'" for: "'z'" == "'z'"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'A' == 'A'
+ok {test-number} - ::Catch::Detail::stringify( '\0' ) == "0" for: "0" == "0"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'Z' == 'Z'
+ok {test-number} - ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" for: "2" == "2"
 # Character pretty printing
-ok {test-number} - null_terminator == '\0' for: 0 == 0
-# Character pretty printing
-ok {test-number} - c == i for: 2 == 2
-# Character pretty printing
-ok {test-number} - c == i for: 3 == 3
-# Character pretty printing
-ok {test-number} - c == i for: 4 == 4
-# Character pretty printing
-ok {test-number} - c == i for: 5 == 5
+ok {test-number} - ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" for: "5" == "5"
 # Clara::Arg supports single-arg parse the way Opt does
 ok {test-number} - name.empty() for: true
 # Clara::Arg supports single-arg parse the way Opt does
@@ -2812,19 +2804,19 @@ ok {test-number} - Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 # Template test case method with test types specified inside std::tuple - MyTypes - 2
 ok {test-number} - Template_Fixture<TestType>::m_a == 1 for: 1.0 == 1
 # Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_default_constructible<TestType>::value for: true
 # Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_default_constructible<TestType>::value for: true
 # Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_trivially_copyable<TestType>::value for: true
 # Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_trivially_copyable<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 2
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # TemplateTest: vectors can be sized and resized - float
 ok {test-number} - v.size() == 5 for: 5 == 5
 # TemplateTest: vectors can be sized and resized - float
@@ -4206,6 +4198,14 @@ ok {test-number} - !(Catch::replaceInPlace(letters, "x", "z")) for: !false
 # replaceInPlace
 ok {test-number} - letters == letters for: "abcdefcg" == "abcdefcg"
 # replaceInPlace
+ok {test-number} - Catch::replaceInPlace(letters, "c", "cc") for: true
+# replaceInPlace
+ok {test-number} - letters == "abccdefccg" for: "abccdefccg" == "abccdefccg"
+# replaceInPlace
+ok {test-number} - Catch::replaceInPlace(s, "--", "-") for: true
+# replaceInPlace
+ok {test-number} - s == "--" for: "--" == "--"
+# replaceInPlace
 ok {test-number} - Catch::replaceInPlace(s, "'", "|'") for: true
 # replaceInPlace
 ok {test-number} - s == "didn|'t" for: "didn|'t" == "didn|'t"

tests/SelfTest/Baselines/tap.sw.multi.approved.txt

@@ -695,33 +695,25 @@ ok {test-number} - lt( "A", "b" ) for: true
 # CaseInsensitiveLess is case insensitive
 ok {test-number} - lt( "A", "B" ) for: true
 # Character pretty printing
-ok {test-number} - tab == '\t' for: '\t' == '\t'
+ok {test-number} - ::Catch::Detail::stringify('\t') == "'\\t'" for: "'\t'" == "'\t'"
 # Character pretty printing
-ok {test-number} - newline == '\n' for: '\n' == '\n'
+ok {test-number} - ::Catch::Detail::stringify('\n') == "'\\n'" for: "'\n'" == "'\n'"
 # Character pretty printing
-ok {test-number} - carr_return == '\r' for: '\r' == '\r'
+ok {test-number} - ::Catch::Detail::stringify('\r') == "'\\r'" for: "'\r'" == "'\r'"
 # Character pretty printing
-ok {test-number} - form_feed == '\f' for: '\f' == '\f'
+ok {test-number} - ::Catch::Detail::stringify('\f') == "'\\f'" for: "'\f'" == "'\f'"
 # Character pretty printing
-ok {test-number} - space == ' ' for: ' ' == ' '
+ok {test-number} - ::Catch::Detail::stringify( ' ' ) == "' '" for: "' '" == "' '"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'a' == 'a'
+ok {test-number} - ::Catch::Detail::stringify( 'A' ) == "'A'" for: "'A'" == "'A'"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'z' == 'z'
+ok {test-number} - ::Catch::Detail::stringify( 'z' ) == "'z'" for: "'z'" == "'z'"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'A' == 'A'
+ok {test-number} - ::Catch::Detail::stringify( '\0' ) == "0" for: "0" == "0"
 # Character pretty printing
-ok {test-number} - c == chars[i] for: 'Z' == 'Z'
+ok {test-number} - ::Catch::Detail::stringify( static_cast<char>(2) ) == "2" for: "2" == "2"
 # Character pretty printing
-ok {test-number} - null_terminator == '\0' for: 0 == 0
-# Character pretty printing
-ok {test-number} - c == i for: 2 == 2
-# Character pretty printing
-ok {test-number} - c == i for: 3 == 3
-# Character pretty printing
-ok {test-number} - c == i for: 4 == 4
-# Character pretty printing
-ok {test-number} - c == i for: 5 == 5
+ok {test-number} - ::Catch::Detail::stringify( static_cast<char>(5) ) == "5" for: "5" == "5"
 # Clara::Arg supports single-arg parse the way Opt does
 ok {test-number} - name.empty() for: true
 # Clara::Arg supports single-arg parse the way Opt does
@@ -2805,19 +2797,19 @@ ok {test-number} - Template_Fixture<TestType>::m_a == 1 for: 1 == 1
 # Template test case method with test types specified inside std::tuple - MyTypes - 2
 ok {test-number} - Template_Fixture<TestType>::m_a == 1 for: 1.0 == 1
 # Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_default_constructible<TestType>::value for: true
 # Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_default_constructible<TestType>::value for: true
 # Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_trivially_copyable<TestType>::value for: true
 # Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_trivially_copyable<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 0
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 1
-ok {test-number} - sizeof(TestType) > 0 for: 1 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # Template test case with test types specified inside std::tuple - MyTypes - 2
-ok {test-number} - sizeof(TestType) > 0 for: 4 > 0
+ok {test-number} - std::is_arithmetic<TestType>::value for: true
 # TemplateTest: vectors can be sized and resized - float
 ok {test-number} - v.size() == 5 for: 5 == 5
 # TemplateTest: vectors can be sized and resized - float
@@ -4195,6 +4187,14 @@ ok {test-number} - !(Catch::replaceInPlace(letters, "x", "z")) for: !false
 # replaceInPlace
 ok {test-number} - letters == letters for: "abcdefcg" == "abcdefcg"
 # replaceInPlace
+ok {test-number} - Catch::replaceInPlace(letters, "c", "cc") for: true
+# replaceInPlace
+ok {test-number} - letters == "abccdefccg" for: "abccdefccg" == "abccdefccg"
+# replaceInPlace
+ok {test-number} - Catch::replaceInPlace(s, "--", "-") for: true
+# replaceInPlace
+ok {test-number} - s == "--" for: "--" == "--"
+# replaceInPlace
 ok {test-number} - Catch::replaceInPlace(s, "'", "|'") for: true
 # replaceInPlace
 ok {test-number} - s == "didn|'t" for: "didn|'t" == "didn|'t"

tests/SelfTest/Baselines/xml.sw.approved.txt

@@ -3142,34 +3142,34 @@ Nor would this
     <Section name="Specifically escaped" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          tab == '\t'
+          ::Catch::Detail::stringify('\t') == "'\\t'"
         </Original>
         <Expanded>
-          '\t' == '\t'
+          "'\t'" == "'\t'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          newline == '\n'
+          ::Catch::Detail::stringify('\n') == "'\\n'"
         </Original>
         <Expanded>
-          '\n' == '\n'
+          "'\n'" == "'\n'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          carr_return == '\r'
+          ::Catch::Detail::stringify('\r') == "'\\r'"
         </Original>
         <Expanded>
-          '\r' == '\r'
+          "'\r'" == "'\r'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          form_feed == '\f'
+          ::Catch::Detail::stringify('\f') == "'\\f'"
         </Original>
         <Expanded>
-          '\f' == '\f'
+          "'\f'" == "'\f'"
         </Expanded>
       </Expression>
       <OverallResults successes="4" failures="0" expectedFailures="0" skipped="false"/>
@@ -3177,88 +3177,56 @@ Nor would this
     <Section name="General chars" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          space == ' '
+          ::Catch::Detail::stringify( ' ' ) == "' '"
         </Original>
         <Expanded>
-          ' ' == ' '
+          "' '" == "' '"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == chars[i]
+          ::Catch::Detail::stringify( 'A' ) == "'A'"
         </Original>
         <Expanded>
-          'a' == 'a'
+          "'A'" == "'A'"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == chars[i]
+          ::Catch::Detail::stringify( 'z' ) == "'z'"
         </Original>
         <Expanded>
-          'z' == 'z'
+          "'z'" == "'z'"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == chars[i]
-        </Original>
-        <Expanded>
-          'A' == 'A'
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == chars[i]
-        </Original>
-        <Expanded>
-          'Z' == 'Z'
-        </Expanded>
-      </Expression>
-      <OverallResults successes="5" failures="0" expectedFailures="0" skipped="false"/>
+      <OverallResults successes="3" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
     <Section name="Low ASCII" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          null_terminator == '\0'
+          ::Catch::Detail::stringify( '\0' ) == "0"
         </Original>
         <Expanded>
-          0 == 0
+          "0" == "0"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == i
+          ::Catch::Detail::stringify( static_cast&lt;char>(2) ) == "2"
         </Original>
         <Expanded>
-          2 == 2
+          "2" == "2"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == i
+          ::Catch::Detail::stringify( static_cast&lt;char>(5) ) == "5"
         </Original>
         <Expanded>
-          3 == 3
+          "5" == "5"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == i
-        </Original>
-        <Expanded>
-          4 == 4
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == i
-        </Original>
-        <Expanded>
-          5 == 5
-        </Expanded>
-      </Expression>
-      <OverallResults successes="5" failures="0" expectedFailures="0" skipped="false"/>
+      <OverallResults successes="3" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
@@ -13592,10 +13560,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_default_constructible&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13603,10 +13571,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_default_constructible&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13614,10 +13582,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_trivially_copyable&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13625,10 +13593,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_trivially_copyable&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13636,10 +13604,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13647,10 +13615,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13658,10 +13626,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 2" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -20066,6 +20034,50 @@ b1!
       </Expression>
       <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
+    <Section name="no replace in already-replaced string" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+      <Section name="lengthening" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            Catch::replaceInPlace(letters, "c", "cc")
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            letters == "abccdefccg"
+          </Original>
+          <Expanded>
+            "abccdefccg" == "abccdefccg"
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+      </Section>
+      <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="no replace in already-replaced string" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+      <Section name="shortening" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            Catch::replaceInPlace(s, "--", "-")
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            s == "--"
+          </Original>
+          <Expanded>
+            "--" == "--"
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+      </Section>
+      <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
     <Section name="escape '" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
         <Original>

tests/SelfTest/Baselines/xml.sw.multi.approved.txt

@@ -3142,34 +3142,34 @@ Nor would this
     <Section name="Specifically escaped" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          tab == '\t'
+          ::Catch::Detail::stringify('\t') == "'\\t'"
         </Original>
         <Expanded>
-          '\t' == '\t'
+          "'\t'" == "'\t'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          newline == '\n'
+          ::Catch::Detail::stringify('\n') == "'\\n'"
         </Original>
         <Expanded>
-          '\n' == '\n'
+          "'\n'" == "'\n'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          carr_return == '\r'
+          ::Catch::Detail::stringify('\r') == "'\\r'"
         </Original>
         <Expanded>
-          '\r' == '\r'
+          "'\r'" == "'\r'"
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          form_feed == '\f'
+          ::Catch::Detail::stringify('\f') == "'\\f'"
         </Original>
         <Expanded>
-          '\f' == '\f'
+          "'\f'" == "'\f'"
         </Expanded>
       </Expression>
       <OverallResults successes="4" failures="0" expectedFailures="0" skipped="false"/>
@@ -3177,88 +3177,56 @@ Nor would this
     <Section name="General chars" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          space == ' '
+          ::Catch::Detail::stringify( ' ' ) == "' '"
         </Original>
         <Expanded>
-          ' ' == ' '
+          "' '" == "' '"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == chars[i]
+          ::Catch::Detail::stringify( 'A' ) == "'A'"
         </Original>
         <Expanded>
-          'a' == 'a'
+          "'A'" == "'A'"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == chars[i]
+          ::Catch::Detail::stringify( 'z' ) == "'z'"
         </Original>
         <Expanded>
-          'z' == 'z'
+          "'z'" == "'z'"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == chars[i]
-        </Original>
-        <Expanded>
-          'A' == 'A'
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == chars[i]
-        </Original>
-        <Expanded>
-          'Z' == 'Z'
-        </Expanded>
-      </Expression>
-      <OverallResults successes="5" failures="0" expectedFailures="0" skipped="false"/>
+      <OverallResults successes="3" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
     <Section name="Low ASCII" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          null_terminator == '\0'
+          ::Catch::Detail::stringify( '\0' ) == "0"
         </Original>
         <Expanded>
-          0 == 0
+          "0" == "0"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == i
+          ::Catch::Detail::stringify( static_cast&lt;char>(2) ) == "2"
         </Original>
         <Expanded>
-          2 == 2
+          "2" == "2"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
+      <Expression success="true" type="CHECK" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
         <Original>
-          c == i
+          ::Catch::Detail::stringify( static_cast&lt;char>(5) ) == "5"
         </Original>
         <Expanded>
-          3 == 3
+          "5" == "5"
         </Expanded>
       </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == i
-        </Original>
-        <Expanded>
-          4 == 4
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/ToStringGeneral.tests.cpp" >
-        <Original>
-          c == i
-        </Original>
-        <Expanded>
-          5 == 5
-        </Expanded>
-      </Expression>
-      <OverallResults successes="5" failures="0" expectedFailures="0" skipped="false"/>
+      <OverallResults successes="3" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
     <OverallResult success="true" skips="0"/>
   </TestCase>
@@ -13592,10 +13560,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_default_constructible&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13603,10 +13571,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-copyable and non-movable std::tuple - NonCopyableAndNonMovableTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_default_constructible&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13614,10 +13582,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_trivially_copyable&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13625,10 +13593,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside non-default-constructible std::tuple - MyNonDefaultConstructibleTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_trivially_copyable&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13636,10 +13604,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 0" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13647,10 +13615,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 1" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        1 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -13658,10 +13626,10 @@ Message from section two
   <TestCase name="Template test case with test types specified inside std::tuple - MyTypes - 2" tags="[list][template]" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
     <Expression success="true" type="REQUIRE" filename="tests/<exe-name>/UsageTests/Misc.tests.cpp" >
       <Original>
-        sizeof(TestType) > 0
+        std::is_arithmetic&lt;TestType>::value
       </Original>
       <Expanded>
-        4 > 0
+        true
       </Expanded>
     </Expression>
     <OverallResult success="true" skips="0"/>
@@ -20065,6 +20033,50 @@ b1!
       </Expression>
       <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
     </Section>
+    <Section name="no replace in already-replaced string" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+      <Section name="lengthening" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            Catch::replaceInPlace(letters, "c", "cc")
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            letters == "abccdefccg"
+          </Original>
+          <Expanded>
+            "abccdefccg" == "abccdefccg"
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+      </Section>
+      <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
+    <Section name="no replace in already-replaced string" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+      <Section name="shortening" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            Catch::replaceInPlace(s, "--", "-")
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
+          <Original>
+            s == "--"
+          </Original>
+          <Expanded>
+            "--" == "--"
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+      </Section>
+      <OverallResults successes="2" failures="0" expectedFailures="0" skipped="false"/>
+    </Section>
     <Section name="escape '" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
       <Expression success="true" type="CHECK" filename="tests/<exe-name>/IntrospectiveTests/StringManip.tests.cpp" >
         <Original>

tests/SelfTest/IntrospectiveTests/Details.tests.cpp

@@ -120,13 +120,13 @@ TEST_CASE( "Optional supports move ops", "[optional][approvals]" ) {
     }
     SECTION( "Move construction from optional" ) {
         Optional<MoveChecker> opt_B( CATCH_MOVE( opt_A ) );
-        REQUIRE( opt_A->has_moved );
+        REQUIRE( opt_A->has_moved ); // NOLINT(clang-analyzer-cplusplus.Move)
     }
     SECTION( "Move assignment from optional" ) {
         Optional<MoveChecker> opt_B( opt_A );
         REQUIRE_FALSE( opt_A->has_moved );
         opt_B = CATCH_MOVE( opt_A );
-        REQUIRE( opt_A->has_moved );
+        REQUIRE( opt_A->has_moved ); // NOLINT(clang-analyzer-cplusplus.Move)
     }
 }
 

tests/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp

@@ -18,7 +18,6 @@
 #include <catch2/generators/catch_generators_adapters.hpp>
 #include <catch2/generators/catch_generators_random.hpp>
 #include <catch2/generators/catch_generators_range.hpp>
-#include <catch2/generators/catch_generator_exception.hpp>
 
 // Tests of generator implementation details
 TEST_CASE("Generators internals", "[generators][internals]") {

tests/SelfTest/IntrospectiveTests/Integer.tests.cpp

@@ -8,6 +8,7 @@
 
 #include <catch2/catch_test_macros.hpp>
 #include <catch2/internal/catch_random_integer_helpers.hpp>
+#include <random>
 
 namespace {
     template <typename Int>
@@ -20,6 +21,58 @@ namespace {
         CHECK( extendedMult( b, a ) ==
                ExtendedMultResult<Int>{ upper_result, lower_result } );
     }
+
+    // Simple (and slow) implmentation of extended multiplication for tests
+    constexpr Catch::Detail::ExtendedMultResult<std::uint64_t>
+    extendedMultNaive( std::uint64_t lhs, std::uint64_t rhs ) {
+        // This is a simple long multiplication, where we split lhs and rhs
+        // into two 32-bit "digits", so that we can do ops with carry in 64-bits.
+        //
+        //            32b    32b    32b    32b
+        //     lhs                  L1     L2
+        //   * rhs                  R1     R2
+        //            ------------------------
+        //                       |  R2 * L2  |
+        //                 |  R2 * L1  |
+        //                 |  R1 * L2  |
+        //           |  R1 * L1  |
+        //           -------------------------
+        //           |  a  |  b  |  c  |  d  |
+
+#define CarryBits( x ) ( x >> 32 )
+#define Digits( x ) ( x & 0xFF'FF'FF'FF )
+
+        auto r2l2 = Digits( rhs ) * Digits( lhs );
+        auto r2l1 = Digits( rhs ) * CarryBits( lhs );
+        auto r1l2 = CarryBits( rhs ) * Digits( lhs );
+        auto r1l1 = CarryBits( rhs ) * CarryBits( lhs );
+
+        // Sum to columns first
+        auto d = Digits( r2l2 );
+        auto c = CarryBits( r2l2 ) + Digits( r2l1 ) + Digits( r1l2 );
+        auto b = CarryBits( r2l1 ) + CarryBits( r1l2 ) + Digits( r1l1 );
+        auto a = CarryBits( r1l1 );
+
+        // Propagate carries between columns
+        c += CarryBits( d );
+        b += CarryBits( c );
+        a += CarryBits( b );
+
+        // Remove the used carries
+        c = Digits( c );
+        b = Digits( b );
+        a = Digits( a );
+
+#undef CarryBits
+#undef Digits
+
+        return {
+            a << 32 | b, // upper 64 bits
+            c << 32 | d  // lower 64 bits
+        };
+    }
+
+
 } // namespace
 
 TEST_CASE( "extendedMult 64x64", "[Integer][approvals]" ) {
@@ -62,6 +115,27 @@ TEST_CASE( "extendedMult 64x64", "[Integer][approvals]" ) {
                                     0xdf44'2d22'ce48'59b9 );
 }
 
+TEST_CASE("extendedMult 64x64 - all implementations", "[integer][approvals]") {
+    using Catch::Detail::extendedMult;
+    using Catch::Detail::extendedMultPortable;
+    using Catch::Detail::fillBitsFrom;
+
+    std::random_device rng;
+    for (size_t i = 0; i < 100; ++i) {
+        auto a = fillBitsFrom<std::uint64_t>( rng );
+        auto b = fillBitsFrom<std::uint64_t>( rng );
+        CAPTURE( a, b );
+
+        auto naive_ab = extendedMultNaive( a, b );
+
+        REQUIRE( naive_ab == extendedMultNaive( b, a ) );
+        REQUIRE( naive_ab == extendedMultPortable( a, b ) );
+        REQUIRE( naive_ab == extendedMultPortable( b, a ) );
+        REQUIRE( naive_ab == extendedMult( a, b ) );
+        REQUIRE( naive_ab == extendedMult( b, a ) );
+    }
+}
+
 TEST_CASE( "SizedUnsignedType helpers", "[integer][approvals]" ) {
     using Catch::Detail::SizedUnsignedType_t;
     using Catch::Detail::DoubleWidthUnsignedType_t;

tests/SelfTest/IntrospectiveTests/RandomNumberGeneration.tests.cpp

@@ -140,7 +140,9 @@ TEMPLATE_TEST_CASE( "uniform_integer_distribution can handle unit ranges",
                     uint32_t,
                     int32_t,
                     uint64_t,
-                    int64_t ) {
+                    int64_t,
+                    size_t,
+                    ptrdiff_t) {
     // We want random seed to sample different parts of the rng state,
     // the output is predetermined anyway
     std::random_device rd;
@@ -493,6 +495,21 @@ TEMPLATE_TEST_CASE( "uniform_integer_distribution is reproducible",
     REQUIRE_THAT(generated, Catch::Matchers::RangeEquals(uniform_integer_test_params<TestType>::expected));
 }
 
+// The reproducibility tests assume that operations on `float`/`double`
+// happen in the same precision as the operated-upon type. This is
+// generally true, unless the code is compiled for 32 bit targets without
+// SSE2 enabled, in which case the operations are done in the x87 FPU,
+// which usually implies doing math in 80 bit floats, and then rounding
+// into smaller type when the type is saved into memory. This obviously
+// leads to a different answer, than doing the math in the correct precision.
+#if ( defined( _MSC_VER ) && _M_IX86_FP < 2 ) ||              \
+    ( defined( __GNUC__ ) &&                                  \
+      ( ( defined( __i386__ ) || defined( __x86_64__ ) ) ) && \
+      !defined( __SSE2_MATH__ ) )
+#    define CATCH_TEST_CONFIG_DISABLE_FLOAT_REPRODUCIBILITY_TESTS
+#endif
+
+#if !defined( CATCH_TEST_CONFIG_DISABLE_FLOAT_REPRODUCIBILITY_TESTS )
 
 namespace {
     template <typename T>
@@ -570,6 +587,8 @@ TEMPLATE_TEST_CASE( "uniform_floating_point_distribution is reproducible",
     REQUIRE_THAT( generated, Catch::Matchers::RangeEquals( uniform_fp_test_params<TestType>::expected ) );
 }
 
+#endif // ^^ float reproducibility tests are enabled
+
 TEMPLATE_TEST_CASE( "uniform_floating_point_distribution can handle unitary ranges",
                     "[rng][distribution][floating-point][approvals]",
                     float,
@@ -579,7 +598,7 @@ TEMPLATE_TEST_CASE( "uniform_floating_point_distribution can handle unitary rang
     CAPTURE( seed );
     Catch::SimplePcg32 pcg( seed );
 
-    const auto highest = uniform_fp_test_params<TestType>::highest;
+    const auto highest = TestType(385.125);
     Catch::uniform_floating_point_distribution<TestType> dist( highest,
                                                                highest );
 

tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp

@@ -107,7 +107,7 @@ TEST_CASE( "Reporter's write listings to provided stream", "[reporters]" ) {
     for (auto const& factory : factories) {
         INFO("Tested reporter: " << factory.first);
         auto sstream = Catch::Detail::make_unique<StringIStream>();
-        auto& sstreamRef = *sstream.get();
+        auto& sstreamRef = *sstream;
 
         Catch::ConfigData cfg_data;
         cfg_data.rngSeed = 1234;

tests/SelfTest/IntrospectiveTests/StringManip.tests.cpp

@@ -57,6 +57,17 @@ TEST_CASE("replaceInPlace", "[string-manip]") {
         CHECK_FALSE(Catch::replaceInPlace(letters, "x", "z"));
         CHECK(letters == letters);
     }
+    SECTION("no replace in already-replaced string") {
+        SECTION("lengthening") {
+            CHECK(Catch::replaceInPlace(letters, "c", "cc"));
+            CHECK(letters == "abccdefccg");
+        }
+        SECTION("shortening") {
+            std::string s = "----";
+            CHECK(Catch::replaceInPlace(s, "--", "-"));
+            CHECK(s == "--");
+        }
+    }
     SECTION("escape '") {
         std::string s = "didn't";
         CHECK(Catch::replaceInPlace(s, "'", "|'"));

tests/SelfTest/IntrospectiveTests/TestSpec.tests.cpp

@@ -236,7 +236,7 @@ TEST_CASE( "Parse test names and tags", "[command-line][test-spec][approvals]" )
         CHECK( spec.matches( *tcD ) == false );
     }
     SECTION( "two wildcarded names" ) {
-        TestSpec spec = parseTestSpec( "\"longer*\"\"*spaces\"" );
+        TestSpec spec = parseTestSpec( R"("longer*""*spaces")" );
         CHECK( spec.hasFilters() == true );
         CHECK( spec.matches( *tcA ) == false );
         CHECK( spec.matches( *tcB ) == false );

tests/SelfTest/IntrospectiveTests/TextFlow.tests.cpp

@@ -152,7 +152,7 @@ TEST_CASE( "TextFlow::Column respects indentation for empty lines",
 
     std::string written = as_written(col);
 
-    REQUIRE(as_written(col) == "  \n  \n  third line");
+    REQUIRE(written == "  \n  \n  third line");
 }
 
 TEST_CASE( "TextFlow::Column leading/trailing whitespace",

tests/SelfTest/TestRegistrations.cpp

@@ -20,7 +20,6 @@ CATCH_REGISTER_TAG_ALIAS("[@tricky]", "[tricky]~[.]")
 #ifdef __clang__
 #   pragma clang diagnostic ignored "-Wpadded"
 #   pragma clang diagnostic ignored "-Wweak-vtables"
-#   pragma clang diagnostic ignored "-Wc++98-compat"
 #endif
 
 /**

tests/SelfTest/UsageTests/Benchmark.tests.cpp

@@ -90,14 +90,14 @@ TEST_CASE("Benchmark containers", "[!benchmark]") {
         };
         REQUIRE(v.size() == size);
 
-        int array[size];
+        int array[size] {};
         BENCHMARK("A fixed size array that should require no allocations") {
             for (int i = 0; i < size; ++i)
                 array[i] = i;
         };
         int sum = 0;
-        for (int i = 0; i < size; ++i)
-            sum += array[i];
+        for (int val : array)
+            sum += val;
         REQUIRE(sum > size);
 
         SECTION("XYZ") {
@@ -121,8 +121,8 @@ TEST_CASE("Benchmark containers", "[!benchmark]") {
                 runs = benchmarkIndex;
             };
 
-            for (size_t i = 0; i < v.size(); ++i) {
-                REQUIRE(v[i] == runs);
+            for (int val : v) {
+                REQUIRE(val == runs);
             }
         }
     }
@@ -135,8 +135,8 @@ TEST_CASE("Benchmark containers", "[!benchmark]") {
             for (int i = 0; i < size; ++i)
                 v[i] = generated;
         };
-        for (size_t i = 0; i < v.size(); ++i) {
-            REQUIRE(v[i] == generated);
+        for (int val : v) {
+            REQUIRE(val == generated);
         }
     }
 

tests/SelfTest/UsageTests/Class.tests.cpp

@@ -39,7 +39,7 @@ namespace {
     };
 
     template <typename T> struct Template_Fixture_2 {
-        Template_Fixture_2() {}
+        Template_Fixture_2() = default;
 
         T m_a;
     };

tests/SelfTest/UsageTests/Compilation.tests.cpp

@@ -313,11 +313,12 @@ TEST_CASE("ADL universal operators don't hijack expression deconstruction", "[co
     REQUIRE(0 ^ adl::always_true{});
 }
 
-TEST_CASE( "#2555 - types that can only be compared with 0 literal (not int/long) are supported", "[compilation][approvals]" ) {
+TEST_CASE( "#2555 - types that can only be compared with 0 literal implemented as pointer conversion are supported",
+           "[compilation][approvals]" ) {
     REQUIRE( TypeWithLit0Comparisons{} < 0 );
     REQUIRE_FALSE( 0 < TypeWithLit0Comparisons{} );
     REQUIRE( TypeWithLit0Comparisons{} <= 0 );
-    REQUIRE_FALSE( 0 > TypeWithLit0Comparisons{} );
+    REQUIRE_FALSE( 0 <= TypeWithLit0Comparisons{} );
 
     REQUIRE( TypeWithLit0Comparisons{} > 0 );
     REQUIRE_FALSE( 0 > TypeWithLit0Comparisons{} );
@@ -330,6 +331,105 @@ TEST_CASE( "#2555 - types that can only be compared with 0 literal (not int/long
     REQUIRE_FALSE( 0 != TypeWithLit0Comparisons{} );
 }
 
+// These tests require `consteval` to propagate through `constexpr` calls
+// which is a late DR against C++20.
+#if defined( CATCH_CPP20_OR_GREATER ) && defined( __cpp_consteval ) && \
+    __cpp_consteval >= 202211L
+// Can't have internal linkage to avoid warnings
+void ZeroLiteralErrorFunc();
+namespace {
+    struct ZeroLiteralConsteval {
+        template <class T, std::enable_if_t<std::is_same_v<T, int>, int> = 0>
+        consteval ZeroLiteralConsteval( T zero ) noexcept {
+            if ( zero != 0 ) { ZeroLiteralErrorFunc(); }
+        }
+    };
+
+    // Should only be constructible from literal 0. Uses the propagating
+    // consteval constructor trick (currently used by MSVC, might be used
+    // by libc++ in the future as well).
+    struct TypeWithConstevalLit0Comparison {
+#    define DEFINE_COMP_OP( op )                                               \
+        constexpr friend bool operator op( TypeWithConstevalLit0Comparison,    \
+                                           ZeroLiteralConsteval ) {            \
+            return true;                                                       \
+        }                                                                      \
+        constexpr friend bool operator op( ZeroLiteralConsteval,               \
+                                           TypeWithConstevalLit0Comparison ) { \
+            return false;                                                      \
+        }                                                                      \
+        /* std::orderings only have these for ==, but we add them for all      \
+           operators so we can test all overloads for decomposer */            \
+        constexpr friend bool operator op( TypeWithConstevalLit0Comparison,    \
+                                           TypeWithConstevalLit0Comparison ) { \
+            return true;                                                       \
+        }
+
+        DEFINE_COMP_OP( < )
+        DEFINE_COMP_OP( <= )
+        DEFINE_COMP_OP( > )
+        DEFINE_COMP_OP( >= )
+        DEFINE_COMP_OP( == )
+        DEFINE_COMP_OP( != )
+
+#undef DEFINE_COMP_OP
+    };
+
+} // namespace
+
+namespace Catch {
+    template <>
+    struct capture_by_value<TypeWithConstevalLit0Comparison> : std::true_type {};
+}
+
+TEST_CASE( "#2555 - types that can only be compared with 0 literal implemented as consteval check are supported",
+           "[compilation][approvals]" ) {
+    REQUIRE( TypeWithConstevalLit0Comparison{} < 0 );
+    REQUIRE_FALSE( 0 < TypeWithConstevalLit0Comparison{} );
+    REQUIRE( TypeWithConstevalLit0Comparison{} <= 0 );
+    REQUIRE_FALSE( 0 <= TypeWithConstevalLit0Comparison{} );
+
+    REQUIRE( TypeWithConstevalLit0Comparison{} > 0 );
+    REQUIRE_FALSE( 0 > TypeWithConstevalLit0Comparison{} );
+    REQUIRE( TypeWithConstevalLit0Comparison{} >= 0 );
+    REQUIRE_FALSE( 0 >= TypeWithConstevalLit0Comparison{} );
+
+    REQUIRE( TypeWithConstevalLit0Comparison{} == 0 );
+    REQUIRE_FALSE( 0 == TypeWithConstevalLit0Comparison{} );
+    REQUIRE( TypeWithConstevalLit0Comparison{} != 0 );
+    REQUIRE_FALSE( 0 != TypeWithConstevalLit0Comparison{} );
+}
+
+// We check all comparison ops to test, even though orderings, the primary
+// motivation for this functionality, only have self-comparison (and thus
+// have the ambiguity issue) for `==` and `!=`.
+TEST_CASE( "Comparing const instances of type registered with capture_by_value",
+           "[regression][approvals][compilation]" ) {
+    SECTION("Type with consteval-int constructor") {
+        auto const const_Lit0Type_1 = TypeWithConstevalLit0Comparison{};
+        auto const const_Lit0Type_2 = TypeWithConstevalLit0Comparison{};
+        REQUIRE( const_Lit0Type_1 == const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 <= const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 < const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 >= const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 > const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 != const_Lit0Type_2 );
+    }
+    SECTION("Type with constexpr-int constructor") {
+        auto const const_Lit0Type_1 = TypeWithLit0Comparisons{};
+        auto const const_Lit0Type_2 = TypeWithLit0Comparisons{};
+        REQUIRE( const_Lit0Type_1 == const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 <= const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 < const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 >= const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 > const_Lit0Type_2 );
+        REQUIRE( const_Lit0Type_1 != const_Lit0Type_2 );
+    }
+}
+
+#endif // C++20 consteval
+
+
 namespace {
     struct MultipleImplicitConstructors {
         MultipleImplicitConstructors( double ) {}
@@ -353,3 +453,17 @@ TEST_CASE("#2571 - tests compile types that have multiple implicit constructors
     REQUIRE( mic1 > mic2 );
     REQUIRE( mic1 >= mic2 );
 }
+
+#if defined( CATCH_CONFIG_CPP20_COMPARE_OVERLOADS )
+// This test does not test all the related codepaths, but it is the original
+// reproducer
+TEST_CASE( "Comparing const std::weak_ordering instances must compile",
+           "[compilation][approvals][regression]" ) {
+    auto const const_ordering_1 = std::weak_ordering::less;
+    auto const const_ordering_2 = std::weak_ordering::less;
+    auto plain_ordering_1 = std::weak_ordering::less;
+    REQUIRE( const_ordering_1 == plain_ordering_1 );
+    REQUIRE( const_ordering_1 == const_ordering_2 );
+    REQUIRE( plain_ordering_1 == const_ordering_1 );
+}
+#endif

tests/SelfTest/UsageTests/Exception.tests.cpp

@@ -119,7 +119,7 @@ TEST_CASE( "When unchecked exceptions are thrown, but caught, they do not affect
     try {
         throw std::domain_error( "unexpected exception" );
     }
-    catch(...) {}
+    catch(...) {} // NOLINT(bugprone-empty-catch)
 }
 
 
@@ -152,7 +152,7 @@ TEST_CASE( "Custom exceptions can be translated when testing for throwing as som
 }
 
 TEST_CASE( "Unexpected exceptions can be translated", "[.][failing][!throws]"  ) {
-    throw double( 3.14 );
+    throw double( 3.14 ); // NOLINT(readability-redundant-casting): the type is important here, so we want to be explicit
 }
 
 TEST_CASE("Thrown string literals are translated", "[.][failing][!throws]") {

tests/SelfTest/UsageTests/Matchers.tests.cpp

@@ -1027,7 +1027,6 @@ TEST_CASE( "Combining MatchNotOfGeneric does not nest",
 }
 
 struct EvilAddressOfOperatorUsed : std::exception {
-    EvilAddressOfOperatorUsed() {}
     const char* what() const noexcept override {
         return "overloaded address-of operator of matcher was used instead of "
                "std::addressof";
@@ -1035,7 +1034,6 @@ struct EvilAddressOfOperatorUsed : std::exception {
 };
 
 struct EvilCommaOperatorUsed : std::exception {
-    EvilCommaOperatorUsed() {}
     const char* what() const noexcept override {
         return "overloaded comma operator of matcher was used";
     }
@@ -1073,7 +1071,6 @@ struct ImmovableMatcher : Catch::Matchers::MatcherGenericBase {
 };
 
 struct MatcherWasMovedOrCopied : std::exception {
-    MatcherWasMovedOrCopied() {}
     const char* what() const noexcept override {
         return "attempted to copy or move a matcher";
     }
@@ -1081,17 +1078,20 @@ struct MatcherWasMovedOrCopied : std::exception {
 
 struct ThrowOnCopyOrMoveMatcher : Catch::Matchers::MatcherGenericBase {
     ThrowOnCopyOrMoveMatcher() = default;
-    [[noreturn]] ThrowOnCopyOrMoveMatcher( ThrowOnCopyOrMoveMatcher const& ):
-        Catch::Matchers::MatcherGenericBase() {
+
+    [[noreturn]] ThrowOnCopyOrMoveMatcher( ThrowOnCopyOrMoveMatcher const& other ):
+        Catch::Matchers::MatcherGenericBase( other ) {
         throw MatcherWasMovedOrCopied();
     }
-    [[noreturn]] ThrowOnCopyOrMoveMatcher( ThrowOnCopyOrMoveMatcher&& ):
-        Catch::Matchers::MatcherGenericBase() {
+    // NOLINTNEXTLINE(performance-noexcept-move-constructor)
+    [[noreturn]] ThrowOnCopyOrMoveMatcher( ThrowOnCopyOrMoveMatcher&& other ):
+        Catch::Matchers::MatcherGenericBase( CATCH_MOVE(other) ) {
         throw MatcherWasMovedOrCopied();
     }
     ThrowOnCopyOrMoveMatcher& operator=( ThrowOnCopyOrMoveMatcher const& ) {
         throw MatcherWasMovedOrCopied();
     }
+    // NOLINTNEXTLINE(performance-noexcept-move-constructor)
     ThrowOnCopyOrMoveMatcher& operator=( ThrowOnCopyOrMoveMatcher&& ) {
         throw MatcherWasMovedOrCopied();
     }